[Branch Migration] Master

This is the final of 3 pull requests applying our branch migration strategy:

https://github.com/mono/MonoGame/wiki/Branch-Migration-Strategy

This final step merges the MonoGame 3.0 release into the `master` branch.

While there are commits here there are no actual files changed because we are accepting the versions of all files from the  `v3.0.0.0` tag.