show water level
prepare using some pawn attributes
Merge branch 'feature/HUD' into feature/behaviour
update and show water level
show temperature
encapsulate active pawn in world method
just ramp the temperature up and down
colour the temperature according to "good", "too hot", "too cold"
water expenditure changes with temperature
Merge branch 'master' into develop
Merge branch 'master' into feature/HUD

Conflicts:
	love2d/layer/hud.lua
	love2d/pawn.lua
Merge branch 'feature/HUD' into develop