gitcheck installation with pip doesn't install 'colored' automatically

Just for your information, maybe it is the way it should be. 
For example:
```bash
# Python 3.5
virtualenv gitcheck
. gitcheck/bin/activate
pip install git+git://github.com/badele/gitcheck.git
gitcheck
     ....
    ImportError: No module named 'colored'
pip install colored
```
I think that the pip does't install `colored` automatically from base.txt. 