Updated FileVersionController.addFile interface, so it can replace the VersionsController one at some point.
Make sure all VersionsController methods deal with File and FileVersion's only.
Little cleanup in Import section.
FileSystem abstraction uses File's now.
Make sure we close FileVersion streams.
Files section of the wiki is now using the same versions controller as the wiki pages do.
Remove string concatenation where file construction is required
Unify Git commit messages.
Remove some dead code.
Create directory also via FileVersion object. Now we can pass author and the like.
Also set author for upload responder.
Added javadoc to VersionsController interface.
Merge pull request #354 from amolenaar/unify-versionscontroller

Unify file and wiki page version controllers
VersionsController.rename should be passed a FileVersion for author and time information.
Let VersionsController.delete take a FileVersion, so author information can be provided.
Add @Override's to SymbolicPage functions.