Fix deploys (and try Travis-CI dpl v2) (pynamodb#773)

Fix Index.query and Index.scan typing issues (pynamodb#748)

Index.query and Index.scan should return a ResultIterator which iterates over instances of the respective model (which is not known at type-check type unless explicitly specified as a generic parameter).

Release 4.3.0 (pynamodb#747)

Release 4.2.0 (pynamodb#715)

Update PyPI classifiers (production, py3.5) (pynamodb#710)

Update release notes for 4.0.0

Update release notes for 4.0.0b3 (pynamodb#659)

Update .travis.yml

Update type stubs for TTL feature (pynamodb#657)

Bump version to 3.4.0