Normalize some of the weirder distributions and releases.

This deals with trival name changes, typos, changes in case, and wierd
interactions with PAUSE (like with Unicode).  There's only a small
number built in right now, I'm sure there can be more later.
Document normalize_dist_names and normalize_releases.
Let a user change any part of a release.

Also change the distvname if the dist or version has been changed.
Merge pull request #24 from book/feature/normalize

Normalize distribution and release data