Add the ability to delete playlists.

Also add the functionality to remove any part of a library. This
may be useful in the future.

Signed-off-by: Alex Waterman <imNotListening@gmail.com>
Add the first part of loadable module support

This contains a simple test module for development purposes. In
the future modules will be used to implement key functionality
like play back and extra library management features.

Signed-off-by: Alex Waterman <imNotListening@gmail.com>