Added Rugged, converted existing Grit code

Description incomplete, coming :soon:  

Here's a [Working demo](http://glittergallery-ropaku.rhcloud.com/) and a [Test Project](http://glittergallery-ropaku.rhcloud.com/rohitpaulk/TestProject1) that I set up.
headcommit doesn't have a tree_id method, so I did this:
```ruby
headtree = barerepo.lookup(barerepo.head.target).tree
```
If you want to use the headcommit, then it's
```ruby
headtree = barerepo.lookup(headcommit).tree
```
Seems right?