Break out protocol implementation into separate library

[zml2008]

Currently both WECUI and WorldEdit have separate implementations of the same protocol, and no independent specification exists.

I'd like to break this implementation into a separate library, ideally licensed LGPL, to allow easily evolving the protocol between WorldEdit, WorldEditCUI, and whatever replacement may come along for WECUI. A secondary goal would be to allow non-WorldEdit plugins/mods to interact with the CUI from the server.

Along with this library I'd like to have proper documentation maintained for current and historical versions of the protocol (only starting from the current version unless someone is interested in further backwards compatibility).

Within this library we can consider possibilities for evolving the protocol like:

• switching to a binary format
• server-defined selection types
• declaring tools

cc @octylFractal, thoughts?