TwigBundle

All rendering about git elements are being moved out to a dedicated bundle: GitonomyTwigBundle.

This code will be factorized between Gitonomy and Gitonomy Browser.

Features:

- [x] Commit cards
- [ ] Files (images & code) - TODO
- [x] Commit list
- [x] Log graph with Ajax scroll
- [x] Diff
- [x] Trees
- [x] Blame
- [ ] Status
- [ ] Branches (list, block?)
- [ ] Tags (list, block?)
- [x] Other minor things (author, pathcrumb, links)

To use this bundle, you need to implement the routing (see UrlGeneratorInterface). I prepared a generic implementation with 5 routes to implement.

I'll move code out of application to a separate repository, and apply it to Gitonomy Browser.