Supplying Bower support

Info, search and install commands available.
``` bash
    aero search bower:jquery
    aero install bower:html5-boilerplate
```

Info command currently does not return any information.

Didn't found any test. They exists?

While it's my first and humble contribution, I'm not comfortable with increasing dependency list. But we can grab Bower packages information with curl, looking for the readme's inside repository addresses provided by the search.

At my tests, I could perform search only after disabling pip ```aero search -d pip jquery```

I'm testing with the following workflow
1. Mod's and save
2. ```python setup.py install --force```
3. ```aero some command```

There is any smarter way?