Adventure Backport

This is a rewrite of like half the entire mod.

Most notably, this mod now only has its effects in adventure mode, which required adding a coremod. As a result, the behavior when clicking a block now matches vanilla.
Caching the return value for canDestroy has no noticeable effect on performance and would only be useful on the client side either way, so it has been removed.
Also, doors and cocoa beans no longer create ghost blocks on the client.
New classes have been written in the Scala programming language.

This is an alpha version and can be unstable and exploitable. Handle with care.