Modules installer

This is a simple modules installer (can't handle multiple files, or requirements yet)

It connects to http://jaspermoduleshub.herokuapp.com/

I added a `walk_packages` on `brain.py` so that modules can be installed in subfolders.
This method name is very misleading. It does not return metadata but checks if a plugin of this name existis in the remote repository. Therefore it should be renamed.