Integrate Subversion info

Since the media repository is handled by Subversion, almost all meta data regarding resources and assets can be found there. Wombat should therefore show as much as this as possible.
To start with, the original creator and the latest change should be shown (along with the log message). If possible, a copy or move operation should not count as a change (so that we show the person who actually altered the asset instead of just moved it in the repo.)
In addition, it should also be possible to view the log. Further functionality could entail allowing users to download previous versions of an asset, but it might be quite complex to implement so it's no requirement.