Add command block properties to locations

command blocks are important things to deal with, even if true scriptors
don't bother using them themselves.
Add entity.interact_with mech

A useful mech, similar to switch but more controlled
Fix the proximity trigger

Who wrote this memleaking nightmare bit of code!?
This needs far more work than this little bandaid, but this is all I
have time for.
Fix some meta

Add, not sub. Identify what move is for.
Lay down the code for an updated playeffect

Using our own enum instead of Mojang's
Make most particle effects functional

A few I can't find an easy match for in the Mojang enum
Fix the while command

How did this even...
Fix somebody changing functionality

This originally returned whether the player was valid at all, now it
seems to return what the name actually implies it is?
Fix player.time meta

The meta lied :o !
Fix material.full

Let's not overcompensate.
Merge pull request #907 from mcmonkey4eva/master

Pull request for some commits