Adds /itembind <bind/clear/get> [command] command with which you can assign command to be run on item click.
These commands are persistent through server restarts/different users.
Allows for special format options($x, $y, $z, $ex, $ey, $ez, $eid, $bx, $by, $bz) which are replaced upon execution with clicked entity/block's x, y, z, etc...
Commands are run with clicker's permission so you dont need to worry about non op players using admin items
