Added RenderNaturalOverlayEvent

I added a simply event for the cancellation of rendering the water texture overlay on the HUD when the player is in water.
This part could just be `if (!MinecraftForge.EVENT_BUS.post(new RenderNaturalOverlayEvent(this.field_78455_a.field_71439_g, p_78447_1_))) this.func_78448_c(p_78447_1_)`
That would be 1 addition instead of 1 removal and 3 additions.

(Lex likes the patches to be as small as possible, not sure if that would apply here though because of the long line)