Fixed spello in comment.
First basic implementation of packets defined by struct defs.
Added support for float packet fields.

Also added some benchmarks and additional packet definitions.
Tidied some protocol tests.
Struct-based packet fields can now serialize themselves.
Some fixes/updates to proto and types.
Additional packets in proto2.
Work-in-progress on proto2 map chunk packet (0x33).
Implemented map chunk packet for proto2 (0x33).
Added TODO for crafting slots for NBT in player inventory.
Added packet multi block change (0x34) to proto2.
Added a couple more packets (and gofmt).
Add explosion packet to proto2 (0x3c).
Implemented packets 0x3d to 0xff for proto2.
Split up proto2, and implemented packet type/id mapping
Moved packet ID reading/writing into {Read,Write}Packet in proto2.
Refactored PacketSerializer to reuse type serialization more.
Further packet field refactoring.
Benchmark and optimize reading string16.
Optimized PacketSerializer.writeString16.