Use YAML_FILENAME_EXTENSIONS for vars files.

Do not combine group_vars with an empty file

The v2 codebase didn't use this previously introduced constant yet.

C.YAML_FILENAME_EXTENSIONS

This addresses a specific case with multiple vars files
in a group_vars/${groupname}/ directory where one of those files
is empty, which returns None instead of an empty dict.

Also changed the setup.py maintainers email to our default support one.

Fixes #11051

fixes #11573

fixed Github links to plugin sources

Fixes #10883

TODO: actually make it check with checkmode
fixes http://github.com/ansible/ansible-modules-core/issues/661

Fixes #10773

fixes #9925

removed time display as it only is provided by command module

also made mail module print nicer without all those 'u'

fix from #10973 by @retr0h

Misspell in mail.py callback.

Looks like little misspell.

Enables 'force basic auth' -feature globally

document `jsonfile` fact cache

Update tests for win_get_url module to test force parameter

assert password or ssh key provided on new image creation