first draft
Merge remote-tracking branch 'upstream/develop' into ebuild_enhanced

Conflicts:
	salt/states/portage_config.py
some fixes
merge fix
other merge fix
added check_extra_requirements function
check_extra_requirements documentation
some fixes
fixes
doc fix
overlay->repository
Merge pull request #5824 from faust/ebuild_enhanced

pkg.installed support for USE flags, overlay and keyword accept
Merge pull request #5898 from terminalmage/quickfix

Fix traceback when there is only one target for pkg.latest
Fix traceback in gem.sources_list

ccefbd5 did not fix the problem. This should take care of it.
Fix traceback in rbenv.versions

52ec9cd did not fix the issue. This should take care of it.
service.running: fix for issue 5894
Fix versionadded sphinx directive for rbenv

I accidentally put the versionadded within the code example, so it
didn't actually work as intended. Also, I added a versionadded directive
to the rbenv module.
correctly capitalize GitHub
use correct Latin abbreviation
various pylint warning fixes