started DH symmetric encryption code

Ignore-this: 7e5e90f98004879aed7fc01f7b2c72cc

darcs-hash:20130823224204-c21fe-566adbe415e58040be3843a34b755fda69060efb
now communication uses symmetric encryption

Ignore-this: 49716b66ce99dcfcbf9c1e8f193ce028

now all communication is encrypted including the greet messages and the pings.
the greet uses public/private key encryption and sends the public DH value to each
other, which is used to create a shared secret.

This shared secret establishes an encrypted session for the particular ip/port combo.
So all remaining communication is encrypted using AES with the session secret.

darcs-hash:20130827045158-c21fe-d99bec5b400470801d5fa2262f3a6adffec1716b
log error loading user

Ignore-this: 4b4e3e596c4d8f26991cdb2ea780611d

darcs-hash:20130827045653-c21fe-8c268688a6dad92199b4a191577e87382ab1375c