improved water physics

default mass for score bubbles is now 0.25 instead of 0.01 (BECAUSE THEY KEPT GETTING SENT TO THE CEILING BY THE WATER)

when an explosion happens the screen shakes (the power of the shaking depends on the distance between the player character and the explosion)

physics iterations are now based on the current fps (they are calculated by multiplying the fps by 2)

made the pod look better

added lazy infinity checks

new level property: gravity

made the dark matter look a lot better (via an effect so if you have no webgl you wont see it)

bug fixes