FIX: API Adaptions for the new History Module

This adapts code locations that were using the old `TagList` interface of the history database. After this Pull Request is merged, the code should compile again. Sorry for this, but separating the changes with functional stages would have been a major head ache.

Note: This contains [Rewrite: Named Snapshot History Management Class](https://github.com/cvmfs/cvmfs/pull/591), [Rewrite: Swissknife History Integration](https://github.com/cvmfs/cvmfs/pull/592) and [Refactor: cvmfs_server Named Snapshot Management](https://github.com/cvmfs/cvmfs/pull/593).
[agreed](https://github.com/reneme/cvmfs/commit/44a6cffcc594cb6a7568756910cabcb7569e17ac). Actually found [another problem](https://github.com/reneme/cvmfs/commit/b8cdb9cfed6179aa993986b7c99effb54eca096e) while writing this extra test. *thumbs up* code review! ;-)