Update physics for attached block to update indirect redstone. Fixes BUKKIT-1858.

When a Lever or Button is modified with .setPowered(), any redstone directly connected is updated correctly, but indirect redstone (on the other side of the block to which the lever is attached, for instance) is not. It seems that the BlockState.update() command does not update the redstone physics of blocks to which an Attachable is attached.

This pull request modifies BlockState.update() to force a physics update on the attached block when the BlockState corresponds to an Attachable object.

https://bukkit.atlassian.net/browse/BUKKIT-1858