This update is so big I more than doubled the jar size! It's a lot better now, please see the changelog below.

Changelog:
-Now checks sign text on paste-rollback.
-Now checks data values on paste-rollback instead of just the material ID.
-Copy and pastes are now progressive.
-All tasks don't take more than a configurable amount of time per tick. Spreads time evenly between operations.
-Increased efficiency of the copy operation by more than 50%.
-Now optionally clears entities on restore rollback operations.
-Optionally ignores blocks in the config defined as air.
-Custom prefixes for developers to use to seamlessly integrate this into their plugin.
-New events to let developers know when operations have completed.
-New WatchDogRegions [BETA] to scale for larger arenas.
-Added a ClearEntities class that is open for developers to use.
-Safely unloads chunks to save memory.
-Improved commands.
-Updated to 1.10
-Added backwards compatibility back to Spigot 1.4.7!
-Now open source under LGPL license.

Known issues:
-Chunks sometimes mysteriously disappear during or after a rollback. Report this if it happens to you, I want to get rid of it as soon as I can.