Added RenderBlockOverlayEvent

I added a simply event for the cancellation of rendering the water texture overlay on the HUD when the player is in water.
Because of the two imports all the lines have changed.
I guess you could have avoided it if you used 
```if (net.minecraftforge.common.MinecraftForge.EVENT_BUS.post(new net.minecraftforge.client.event.RenderBlockOverlayEvent(this.field_78455_a.field_71439_g, p_78447_1_))) ```return;