Introducing sanitizer callbacks in transport layer.
Merge pull request #722 from sophron/sanitize-transport-data

Introducing sanitizer callbacks in transport layer
Order imports according to PEP8.
Remove unused method remove_peer.
Remove unused method addCryptoPeer.
Dump connect_to_peers.
Remove unused argument from get_crypto_peer.
Remove more unused stuff
Remove parts of the old handshake protocol that are not used anymore.

* Remove TransportLayer.get_profile, CryptoTransportLayer.get_profile, CryptoTransportLayer.create_peer, CryptoTransportLayer.send_enc, CryptoTransportLayer._init_peer
Various cleanup

* Remove TransportLayer.timeouts
* Convert a comment to a docstring