…N, DDN, SARSA) with tests and demo notebooks, plus bug fixes and CI modernization (aimacode#1323)

* defined the PlanningProblem as a specialization of a search.Problem & fixed typo errors

* fixed doctest in logic.py

* fixed doctest for cascade_distribution

* added ForwardPlanner and tests

* added __lt__ implementation for Expr

* added more tests

* renamed forward planner

* Revert "renamed forward planner"

This reverts commit c4139e5.

* renamed forward planner class & added doc

* added backward planner and tests

* fixed mdp4e.py doctests

* removed ignore_delete_lists_heuristic flag

* fixed heuristic for forward and backward planners

* added SATPlan and tests

* fixed ignore delete lists heuristic in forward and backward planners

* fixed backward planner and added tests

* updated doc

* added nary csp definition and examples

* added CSPlan and tests

* fixed CSPlan

* added book's cryptarithmetic puzzle example

* fixed typo errors in test_csp

* fixed aimacode#1111

* added sortedcontainers to yml and doc to CSPlan

* added tests for n-ary csp

* fixed utils.extend

* updated test_probability.py

* converted static methods to functions

* added AC3b and AC4 with heuristic and tests

* added conflict-driven clause learning sat solver

* added tests for cdcl and heuristics

* fixed probability.py

* fixed import

* fixed kakuro

* added Martelli and Montanari rule-based unification algorithm

* removed duplicate standardize_variables

* renamed variables known as built-in functions

* fixed typos in learning.py

* renamed some files and fixed typos

* fixed typos

* fixed typos

* fixed tests

* removed unify_mm

* remove unnecessary brackets

* fixed tests

* moved utility functions to utils.py

* fixed typos

* moved utils function to utils.py, separated probability learning classes from learning.py, fixed typos and fixed imports in .ipynb files

* added missing learners

* fixed Travis build

* fixed typos

* fixed typos

* fixed typos

* fixed typos

* fixed typos in agents files

* fixed imports in agent files

* fixed deep learning .ipynb imports

* fixed typos

* added SVM

* added .ipynb and fixed typos

* adapted code for .ipynb

* fixed typos

* updated .ipynb

* updated .ipynb

* updated logic.py

* updated .ipynb

* updated .ipynb

* updated planning.py

* updated inf definition

* fixed typos

* fixed typos

* fixed typos

* fixed typos

* Revert "fixed typos"

This reverts commit 658309d.

* Revert "fixed typos"

This reverts commit 08ad660.

* fixed typos

* fixed typos

* fixed typos

* fixed typos

* fixed typos and utils imports in *4e.py files

* fixed typos

* fixed typos

* fixed typos

* fixed typos

* fixed import

* fixed typos

* fixed typos

* fixd typos

* fixed typos

* fixed typos

* updated SVM

* added svm test

* fixed SVM and tests

* fixed some definitions and typos

* fixed svm and tests

* added SVMs also in learning4e.py

* fixed inf definition

* fixed .travis.yml

* fixed .travis.yml

* fixed import

* fixed inf definition

* replaced cvxopt with qpsolvers

* replaced cvxopt with quadprog

* fixed some definitions

* fixed typos and removed unnecessary tests

* replaced quadprog with qpsolvers

* fixed extend in utils

* specified error type in try-catch block

* fixed extend in utils

* fixed typos

* fixed learning.py

* fixed doctest errors

* added comments

* removed unnecessary if condition

* updated learning.py

* fixed imports

* removed unnecessary imports

* fixed keras imports

* fixed typos

* fixed learning_curve

* added comments

* fixed typos

* removed inf and isclose definition from utils and replaced with numpy.inf and numpy.isclose

* fixed doctests

* fixed numpy imports

* fixed superclass call

* removed utils import from 4e py file

* removed unnecessary norm function in utils and fixed Activation definition

* removed unnecessary clip function

* removed unnecessary import and functions from utils

* added tests and fxed some functions

* fixed doc

* fixed typos in gui folder

* removed unnecessary Keras classes and updated pytest.ini

* fixed some details

* readded Keras classes

* fixed import

* fixed some parameters

* removed unnecessary superclass

* fixed neural net

* added LinearLearner, LogisticLearner with tests and fixed NeuralNetLearner and PerceptronLearner

* removed random_weights and substituted with np.random.uniform

* fixed imports

* Revert "fixed imports"

This reverts commit aaf9c7b.

* Revert "removed random_weights and substituted with np.random.uniform"

This reverts commit 70d662b.

* revert

* fixed typo

* fixed .ini and DecisionTreeLearner

* fixed tests

* removed main and fixed AutoencoderLearner

* revert NeuralNetLearner and PerceptronLearner definition

* fixed all tests and removed Learner class

* fixed tests

* fixed tests

* fixed tests

* fixed some function definition

* fixed verbose definition

* fixed tests

* fixed tests

* fixed tests

* updated .travis.yml

* fixed .travis.yml

* fixed .travis.yml

* fixed all tests

* fixed requirements.txt

* fixed .travis.yml

* update .travis.yml

* rollback .travis.yml

* rollback tests

* fixed output layer with softmax as activation function

* updated yml

* updated requirements.txt

* fixed svc

* fixed syntax warns

* fixed syntax warns

* removed 3.8

* added python 3.8 support

* fixed doctests

* fixed spaces and doctest

* added SVR with r2 and accuracy metrics

* fixed imports

* fixed tests

* removed not allowed imports

* fixed

* fixed keras

* fixed

* updated requirements.txt

* Fix NotImplementedError raises, docstring escapes, keras lr arg and flaky value_iteration test

* Add Kalman filter (Section 15.4)

* Add EM for Gaussian mixtures (Section 20.3)

* Add Baum-Welch for HMM learning (Section 20.3)

* Add dynamic decision network POMDP look-ahead agent (Section 17.4)

* Add EM for Bayes net with hidden variables (Section 20.3.2)

* Add non-cooperative game theory: dominance, Nash equilibria, zero-sum LP (Chapter 18)

* Add cooperative game theory (Shapley, core) and social choice (voting, Vickrey auction)

* Add contract net protocol and alternating-offers bargaining (Section 18.4)

* Add dynamic Bayesian network with unrolling and exact filtering (Section 15.5)

* Add SARSA on-policy TD-learning agent (Section 21.3)

* Add iterated elimination of dominated strategies (Section 18.2)

* Add executed demo notebooks for the new 4e algorithms

* Add tests from the book and solutions manual (zero-sum 17.17, saddle point, battle of the sexes, stag hunt, DBN sequence, Kalman steady state)

* Fix spelling typos in comments, docstrings and data labels

* Update README: modern Python version support and typo fix

* Clean up game_theory.py line lengths for flake8

* Modernize CI: bump Travis Python versions and add GitHub Actions workflow

* Add tests for SAT heuristics/restarts and n-ary CSP extras

Cover the previously untested non-book algorithms so they match the
baseline test coverage:

- test_dpll_branching_heuristics / test_cdcl_restart_strategies exercise
  every branching heuristic (moms, momsf, posit, dlis, dlcs, jw, jw2, zm)
  and restart strategy (no_restart, luby, glucose) on small SAT/UNSAT
  instances.
- test_nary_csp, test_ac_solver_classes, test_crossword, test_kakuro
  cover NaryCSP/Constraint, the ACSolver/ACSearchSolver classes directly,
  and the Crossword/Kakuro models.

* Rename files to follow snake_case and 4e conventions

- game_theory.py -> game_theory4e.py (module written against 4th-edition
  chapter 18 numbering, consistent with the other 4e-structured modules);
  test file, notebook and README links updated accordingly.
- making_simple_decision4e.py -> making_simple_decisions4e.py to match the
  book chapter title 'Making Simple Decisions'.
- planning_graphPlan.ipynb -> planning_graph_plan.ipynb and
  knowledge_FOIL.ipynb -> knowledge_foil.ipynb (snake_case).
- images/pluralityLearner_plot.png and images/knowledge_FOIL_grandparent.png
  renamed to snake_case; notebook references updated.

* Rename camelCase identifiers to snake_case (PEP 8)

Make function and variable names consistent with the snake_case style
used across the rest of the codebase:

- planning.py: the *_graphPlan example helpers become *_graph_plan, plus
  graphPlan_solution, initialPlan, nConstraints, nPartial.
- nlp.py: loadPageHTML, initPages, stripRawHTML, determineInlinks,
  findOutlinks, onlyWikipediaURLS, getInLinks, getOutLinks and their local
  variables (pagesIndex, pagesContent, inLinks, outLinks, etc.).
- Updated all call sites in tests and notebooks, and snake_cased the
  affected test names and test-local variables.

Class names (PascalCase) and the canvas strokeWidth method, which mirrors
the JS canvas API, are intentionally left unchanged.