Devoncarew git actions

Address #696, moving git operations from spark menu to the context menu.

- added behavior to expand (as well as select) a folder at the end of a git clone
- moved the filtering of the `.git` folder from the workspace to the files view. It will be useful in the future to get resource change notifications for git metadata
- changed the git actions to implement `ContextAction`, and removed most of them from the spark menu. It's an open item to change the actions to act on the given `Project`, instead of a fixed git repository.
- changed the toolbar to emphasize git, open folder, and run
- added git status info for projects in the files view, to let users know when a project is using git

![screen shot 2014-01-15 at 12 29 40 pm](https://f.cloud.github.com/assets/1269969/1925147/a676137c-7e2c-11e3-9c86-3f8ecbafa881.png)
![screen shot 2014-01-15 at 12 29 45 pm](https://f.cloud.github.com/assets/1269969/1925149/a96f15b0-7e2c-11e3-8677-3a4e47373468.png)
![screen shot 2014-01-15 at 12 30 01 pm](https://f.cloud.github.com/assets/1269969/1925151/ac767596-7e2c-11e3-865b-3042491c31c5.png)

@gaurave @dinhviethoa