Sticky piston break unmovable blocks, such as saplings, crops, leaves, liquids, melons and pumpkins when pulled

Here is how to fix it:
When a sticky piston retracts, it calls the method which moves the blocks.
In 14w18a this looks roughly like this:
if (!somebool) {
moveblocks();
}

In older versions it looked like this (which would also prevent this bug now):
if (!somebool && blockInFront.getMatierial() != Material.air && isMovable(blockInFront) && (blockInFront.getMobilityFlag() == 0 || blockInFront == Blocks.piston || blockInFront == Blocks.sticky_piston)) {
moveblocks();
}

I think we just accidently removed these checks when testing things. Adding them again should fix this bug.

also with saplings, crops, leaves and liquids says: MC-54637