Squashed commit of the following:

commit c5d70f3ddcefc2be6e5ce4112412e8d1c1dc87c1
Author: Nicolai Czempin <contact@czempin.de>
Date:   Sat Apr 19 16:06:15 2014 +0200

    some movement
Add layer system.
Merge branch 'master' of https://github.com/nczempin/lizard-journey

Conflicts:
	love2d/world.lua
reworked sound management, music is now separated from other sounds and all sound files (including music) will have to be initialized via soundinit.lua.
The names they are referred to as are also defined there.
Fixed issue where states where keypresses did not lead to status change due to typo.
Merge branch 'master' of https://github.com/nczempin/lizard-journey
Map generator creates lakes now.
Merge branch 'master' of github.com:nczempin/lizard-journey
Add zoom.
Merge branch 'master' of https://github.com/nczempin/lizard-journey
draw creep in front
more interesting movement and colour
Merge branch 'master' into feature/behaviour

Conflicts:
	love2d/pawn.lua
	love2d/world.lua