Now clients send message to supernodes, sending a new filename

TODO:
(1) Module disconnect for client and supernode
	(1.1) Client disconnect: send a message to supernode, asking it to remove all files. Supernode checks all files from that client and ask other supernodes to remove it from their hashtable.
	(1.2) Supernode disconnect: send a message to all of his clients. Clients disconnect and start connecting again sending their filenames to the new supernode.

(2) For every filename received, the supernode must send a message to the other supernodes, so they can add it to their HT, <filename, supernodeAddress>

(3) Implement the download module