Improve release documentation 797

Fixes #797 
Perhaps this should be http://doc-dev.clusterhq.com/gettinginvolved/infrastructure/release-process.html (from buildbot, instead).

Also, it'd be nice to not have to scroll, when reviewing, to see where the link is to. Either just use `<>` to specify the link, or have the out-of-line link at the end of the paragraph and/or section.