Improved Door Code and Removed Hack

Improved some of our door code by giving some of our variables real
names. Also found a hack in BaseDimDoor.isDropped() and a strange
comment that said "I have no idea, but sometimes this is returned as the
blockID instead of metadata."  I finally figured out that due to some
random mistake introduced in another function, idDropped() sometimes
received a block ID instead of metadata, which is what that comment
referred to. I fixed the cause and removed the hack.