Proof of concept: recommend that user adds README, LICENSE, and .gitignore files

Would like to see the empty repo page recommend that the user add README, LICENSE, and .gitignore files.

![image](https://cloud.githubusercontent.com/assets/1192780/4299119/980d139c-3e31-11e4-87d5-4f173541e013.png)

What's needed to make this happen:
- [ ] GitLab needs to be able to init repo without someone pushing an inited repo
- [x] `/new/master?file_name=README.md` needs to open an editor to create a new file of the specified name
- [ ] Visiting `/new/master?file_name=README.md` in an empty repo should return the new file page rather than a 404
- [ ] Selecting commit from `/new/master?file_name=README.md` when the repo is empty should init the repo and make the commit
- [ ] Test haml code (I just threw this together without testing the links) and styling