Add meta notes on entity type requirement

A lot of entity mechanisms require living entities or similar.
Make foreach,repeat,while delayable

Use a callback engine to make it possible to add delays in
foreach/repeat/while commands.
Debug definition filling

Also fix a variety of bugs
Allow waiting in instant queues

Use at your own risk!
General code cleaning

Unused imports and all that
Merge branch 'master' of https://github.com/aufdemrand/Denizen
Make the shoot command holdable

- ~shoot now available!
Also make getEyeLocation work a bit nicer
Make the rotate command holdable

Yay for spreading holdability
Allow holding in instant queues

- ~holdable commands now work like wait, forcing instant queues to be
timed
Merge pull request #815 from mcmonkey4eva/master

Pull request for awesome features