Removed April Fools joke.

Game version is now alpha 4, promise!
Fixed invisibility potions.

Fixed check for if an entity is visible to the player (needed inversion)
and extended invis potion time to 2 minutes.
Updated inventory image.

Updated inventory image in preparation for listing current status
effects and other things (show hp/mana/food values?).
Displayed current status effects.

All status effects on the player are now shown on the inventory screen
at the right hand side.
Changed status effect rendering.

No longer renders redundant effects (two invis effects at once, heal
level 1&2), instead renders the most relevant effect of each type
(strength takes first priority, then time).
Added rats.

Added rat entity (same AI as skeleton but faster and much less HP) and
prepared player entity for rendering mounted entities (slimes).
Added mountable function for living entities.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	Roguelike/src/org/tilegames/hexicube/topdownproto/Game.java
	Roguelike/src/org/tilegames/hexicube/topdownproto/entity/EntityLiving.java
	Roguelike/src/org/tilegames/hexicube/topdownproto/entity/EntityPlayer.java
	Roguelike/src/org/tilegames/hexicube/topdownproto/entity/EntitySkeleton.java
	assets/sounds/bg.ogg