Setup for an var/archives directory
Added a couple of functions to help with archiving repositories.

One archives any directory, the other archives Repository objects
Cleaned up, added forked_from field, and updated signals to archive on delete

Forking should work as well (need to test)

Also changed post_save signal so that if the repo already exist on
disk, we just archive it and create a blank (or cloned) repo in its
place.
Updated timestamped filenames

Tar didn't like the colons... it didn't want to untar the other
timestamps.
Prevent ridiculous recursive tar archives
Forking works!

Was cloning wrong. Fixed that.
Merge branch 'feature/fork' into develop
Paginated commits
Moved git show pygments to a filter, instead of get_show() in Repository
Get the basenames for items in the tree view
Optimized get_tree a little and improved file order
Fixed breadcrumbs and did a little template refactoring
Show current ref in page header
Added refs to commit list