Having MC2 look like MC1

I'm currently working on making MC2 really look like MC1. This is what results from the discussion we had with my mentor when he visited me two weeks ago. My main goal is to have the same features as in MC1 to ease adoption, not more not less.

What have changed recently:

- I've implemented the 'Changes' feature. Changes are calculated but a tool must be built to display them.
- I've also implemented a browser for repositories. This is really like the Repository Browser in MC1.
- Some classes avoids the creation of equal instances (the slices, the slice stati...).
- Corrects a bug with the directory repository.

Here is a screenshot of the two MC2 browsers. When there are '?' around a button label, that means the feature is not yet implemented.



What I plan to do in future weeks:

- Finish the implementation of the 'Changes'
- Change the format of commits to contain textual information (a zip with the source code, the change comment, and the binary data that is already generated)