Add comments about several of the environments.
Add comments about several of the environments.

Cleaned up some problems that caused minor warnings.

Added environments for object methods and members, with non-indexing variants.
This includes reduced use of the indexsubitem setting, allowing more robust
index generation.

Removed some unused definitions.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator