Equation to convert mouse coords to world coords.

In case you lose it, it's this:
self.worldMouseX = (self.camera.newPositionX -
(self.camera.newWeightedScale*aspect))
+x*((self.camera.newWeightedScale*aspect)/self.width)*2
self.worldMouseY = (self.camera.newPositionY -
self.camera.newWeightedScale)
+y*((self.camera.newWeightedScale)/self.height)*2

Probably a bit confusing. Whatever. It works.