Closes#85. Nick collisions caused by internal clients are handled fine now, including the following cases:
- Abusing spawnClient to create a user with the same nick as a relay client, but with a lower TS.
- When both an UID (e.g. 42XAAAAAA) and a tagged UID (_42XAAAAAA) exist on the same network (the two will both try to take the same nick of _42XAAAAAA/net over the relay).
The case where changing NICK from a long cut-off nick to another long cut-off nick is also mitigated. somelongnick/net won't show nick changes to somelongnic//net if the old and new nicks have give the same normalized relay nick.
This introduces a new dependency, expiringdict, from https://pypi.python.org/pypi/expiringdict/1.1.2, which is used as a cache for flood prevention.
