Add support for git urls

Add support for git urls.
Now following git url formats are supported: ([source](https://www.npmjs.org/doc/files/package.json.html#git-urls-as-dependencies))
```
git://github.com/user/project.git#commit-ish
git+ssh://user@hostname:project.git#commit-ish
git+ssh://user@hostname/project.git#commit-ish
git+http://user@hostname/project/blah.git#commit-ish
git+https://user@hostname/project/blah.git#commit-ish
```