Fix typo/logic error in previous commit
Send block updates even when applyPhysics is false.  Fixes BUKKIT-3971
The CraftBlock class is setting bit 0x4 of the update flag when bit 0x2
should in fact be set here. Bit 0x2 means "do updates"; bit 0x4 means
"don't do updates if the world is static, even when bit 0x2 is set".
Correct event handling for dispensing filled buckets. Fixes BUKKIT-4046

We only go through event creation and calling when dispensing filled buckets
if the bucket is able to place its liquid. However, the check for this is
incorrect so the event is not called when a block liquids can destroy is
in front of the dispenser. This commit fixes the check to match the checks
vanilla does when actually using the bucket.