Allow for blocks to act like Sand

Was looking at this, but I got a bit stuck. You override updateTick to add custom triggers, but that is when it normally will check if it should fall. checkFallable cant be called because its a private method

I was thinking of making a sandstorm. looks like sand block, when the weather is storming it transforms into a floating liquid block which flows upwards, and spreads out at it's max height. the flowing block stays what it is until the weather changes back, and it transforms into falling sand.

Added by #154