Added BOW_SHOOT type which fires when a player shoots a bow.
Added CHANGE_ARROW effect (1.13+ only) which allows you to visually change shot arrows to any entity (and optionally spawn the entity when the arrow lands).
Added more directions to the BOOST effect. It now accepts 'UP', 'DOWN', 'FORWARD', and 'BACKWARD'. Example usage: 'BOOST:FORWARD:10'