Improvements over last version of library:

* New delivery type: Reliable sequenced (Lost packets are resent but late arrivals are dropped)
* Disconnects and shutdown requests are now queued properly, so calling shutdown will still send any queued messages before shutting down
* All messages are pooled/recycled for zero garbage
* Reduced CPU usage and lower latencies (in the <1 ms range, but still) due to better socket polling
* All public members of NetPeer/NetConnection are completely thread safe
* Larger number of delivery channels
* More exact roundtrip measurement
* Method serialize entire objects via reflection
* Unique identifier now exists for all peers/connections
* More flexible peer discovery; filters possible and arbitrary data can be sent with response
* Much better protection against malformed messages crashing the app

API enhancements:
* NetPeerConfiguration immutable properties now locked once NetPeer is initialized
* Messages cannot be send twice by accident
* Impossible to confuse sending and receiving buffers since they're different classes
* No more confusion if user should create a buffer or preallocate and reuse