rename git menu items; remove print; git commit applies to more items

This PR:

- renames some of the git context menu items (feedback welcome)
- removes some print() calls from the git code
- makes the commit menu enabled for files a project, as well as for the project itself

@gaurave, @dinhviethoa

![screen shot 2014-02-27 at 10 04 04 am](https://f.cloud.github.com/assets/1269969/2285911/bb290a34-9fda-11e3-8880-09a032e61905.png)
![screen shot 2014-02-27 at 10 09 28 am](https://f.cloud.github.com/assets/1269969/2285912/bb299d6e-9fda-11e3-9af4-9d1cf2de8858.png)