MisterHouse 3.0 Release

I think we are ready to push master into stable and release 3.0.  The master branch seems to have been working fine for those who have been using it for the past week, at least I have not heard otherwise.  Besides the documentation, today's pushes solved a few nits that shouldn't and haven't caused any issues for me.  I also added extensive notes to https://github.com/hollie/misterhouse/wiki/Changelog.

So with that, we should be good.  I confess I didn't pay attention to how the versioning is supposed to work.  Should I be updating VERSION in the master branch?  I assume that since it is set to unstable, it only gets changed in the stable branch.