Updated HISTORY.md and version constants for version 4.5.3.

Final steps for new release 4.5.2 : change of version constants in 'c…

…urses.h' and 'docs/HISTORY.md', a few recent changes logged in the latter, updated 'docs/USERS.md'.

Brought HISTORY.md and version constants up to date

Merge pull request #326 from Bill-Gray/portable-panel_hidden

make panel_hidden portable, prepare release 4.5.0

Brought HISTORY.md and MANUAL.md up to date

Updated MANUAL.md, HISTORY.md, and version constants for a new release.

Update version constants and file dates in curses.h and HISTORY.md

Updated version constants and HISTORY.md for v4.3.5

Time for a version update. I expect there will be another one quite s…

…oon, to include clangen's single-threaded WinGUI changes, but thought it'd be good to have a 'changes to date' (there have been many) version followed by a 'single-threaded WinGUI' version.

Version change from 4.3.2 to 4.3.3.