Untabify versionlock method
Don't versionlock packages whose version is a *.
Refactor versionlock

It was getting too long, with too many comments, and there are some
intrusive changes in the pipeline.
Add unit tests for the locked_all_packages method.
Add unit tests for prepare-lock-lists.
Improve the tests for versionlocking.
Merge pull request #104 from piojo/spma-report-globs

Detect when packages with wildcards cannot be versionlocked.