Adding support for S3 as a fileserver backend
Update s3fs.py
use sets for platform tests for enabling/disabling modules
harmonize at.BAD & system.UNSUPPORTED => disable
Fix some pep8
Remove check_dns arg from minion_config, Fixes #4811

All use of the check_dns arg was removed in
598d715d28b15202cdba87b6882ef96c90d4f075.  No longer needed.

Arg was removed from both apply_minion_config and minion_config in
config.py, as well as all their call points.
Merge pull request #4949 from UtahDave/develop

Add links to 0.15.1 Salt Windows installers
Add **kwargs so we don't break API calls
Update debian changelog for 15.1
Merge pull request #4952 from KB1JWQ/develop

Update debian changelog for 15.1
update rpm spec to patch release 0.15.1
Merge pull request #4956 from herlo/develop

update rpm spec to patch release 0.15.1
fix "minon" misspelling; format example bash command
Merge pull request #4959 from cvrebert/patch-1

fix "minon" misspelling; format example bash command
Update s3fs.py
Merge pull request #4941 from hulu/virtual-disable

harmonize at.BAD & system.UNSUPPORTED => disable
Only import pwd in one place, Fixes #4808

Also make it so windows minions can import master.py without barfing on
the original pwd import
Small copyedit and pep8 fix
Use salt.utils.is_windows()
fix some Sphinx warnings