LavaFlow issue and WaterWave Improvements

LavaFlow not cleaning while shift held:
  - The user used to be able to hold shift indefinitely and the Lava would stay there until they released shift, now the blocks will start to revert based on the time set by SHIFT_REMOVE_DELAY.

WaterWave now works with WaterPassive and doesn't create currents:
  - WaterWave now causes WaterPassive to happen if the user is holding shift while submerged in water.
  - WaterWave was originally deleting the source block that the player was using, this was causing water to be displaced and currents were forming in the absence of water. WaterWave no longer deletes the source block.