Various utils/git fixes

- Remove duplicate commit method
- Fix grouping function
- Add partial wrap for update_refs method for pushes
Add datetime template tag for converting epoch utc
Git.revtree now returns an OrderedDict

- revtree ordering is sorted(folder) + sorted(files)
Add kwargs for Commit.tree to force OrderedDicts
Add basic project view functionality

- Allows the end user to see the top-level tree