Implements 1.8 codecs (0x41 up to 0x49) Partially completes #131

Implement ServerDifficulty codec.
Implement CombatEvent codec.
Add 0x43 (Camera).
Packet 0x48 codec added.
Packet 0x44 added (WorldBorder)
Packet 0x45 added. (Title). Some formatting.
Add 0x49 (Entity update NBT). Using varLong now in WorldBorder.

Signed-off-by: William Lebel <lebelwilliam@gmail.com>
Looking at this, and just wondering, aren't variables supposed to be made according to https://github.com/GlowstoneMC/Glowstone/wiki/Code-Style? "In the message codecs, each read from the buffer should be assigned to a variable before the message is constructed."