Switch to new Gobject Introspection bindings

This lays the groundwork for melange to use the new Gobject Introspection bindings. Due to the huge architectural changes melange had to be rewritten from scratch.

Major changes:
- Drop ``jscore`` for the ``python<->js`` bridge. Replace it with ``WebView.execute_script`` to send data from python to js. In order to get data from js to python the widgets sets the ``window.location.href`` attribute which is trapped by webkit and handled in the python code
- Instead of serving the files through a webserver, rewrite paths to point to absolute paths in the filesystem so webkit can load them from there. This saves us an extra thread and is easier to implement as each widget is now responsible for its own files.
-  Port to Gobject Introspection Gtk3
- Update mootools

Opening this PR to keep track of the development. Further commits will be attached here. This will fix #10