reordered the functions so that they are closer to their first call place
- Reduced the scope of the texture. They have been downgraded from class properties to local function variables.
- Removed the class property for the highscore SKNode as it's not needed to have such a big scope
- the contact function now extracts the bird from the physics bodies in contact instead of using the class property "bird". I am trying to remove the need to have the bird a class property.
	- the contact function is already coupled with all the nodes it requires via the 'categoryBitMask'

Pup