Refactor gfx.py to use bytearrays. Fix some graphics dumping functions.
gfx.py: Forgot to add rom_offset.
Rewrite the lz compressor.
Merge remote-tracking branch 'yenatch/master'

Conflicts:
	pokemontools/gfx.py
Merge pull request #78 from yenatch/master

Refactor gfx.py with bytearrays, fix graphics dumps, rewrite the compressor.