Add git tools

[Dovyski]

Add a git panel to allow users to use git within Codebot. The panel should also be smart enough to detect any .git directory in the project and start using it for source control.

I think the best way of implementing this task is creating a plugin, a panel and a backend (pretty much what is done for the assets finder, for instance).

[Dovyski]

This is required for git tools.

[Dovyski]

This diff tool is also required.

[Dovyski]

Here is a pure implementation of git in JS.