Add Linux yum_omnibus Distro, Amazon Linux AMI
Support all Amazon Linux versions

All current versions are based on Fedora and EL6, and as Omnibus
supports them, so can we.
Add integration test for Amazon Linux AMI
Merge pull request #181: Support Amazon Linux

Thanks to @TheAlphaTester.
Add #181 to changelog
Do not update gh-pages on prereleases

Also add version number to the commit message on actual releases.
Merge pull request #194 from tmatilai/prerelease

Ensure that pre-releases don't update main docs