Bukkit

General:
-Removed some unused classes and methods, which reduced the jar size a bit.
-Updated the version number in the yml file and jar manifest.
-Added a little suggestion to the readme about getting rid of an old database folder when you delete your worlds to generate new ones.

For memory efficiency, only about 10 changes will be kept for any particular block.*

*The number recorded can actually be a bit higher than 10, since the ceiling for a deletion operation is actually 14 changes. In other words,
 the system won't actually delete any recorded changes until there are 14 or more changes for a particular block.