Cleanup of the tooltip and moving code into functions

Hopefully you find this helpful. I've created some useful functions and generalized a lot of the tooltip text so we don't have to check for which type of item things are anymore.

I've also solved the wrapping issue you described for the longer potions.

With a bit more work, we may even be able to colour the item stats differently so that it is a lot more readable. http://love2d.org/forums/viewtopic.php?t=35516&p=105417