-Particles can now start or end at a certain tick, and loop or not loop.
-Added setSize(), getWidth() and getHeight() functions.
-Added setOffset(), getOffsetX(), and getOffsetY() functions.
-Added setAnimRate() and getAnimRate() functions.
-Added scripted particles which can not face the player, having their angles be absolute in the world instead of relative to the camera.
-set/getFacePlayer() functions added.
Flying NPC's get knocked back properly, and their vertical speed has been increased.
Flying NPC's vertical flying speed can be changed by npc.setFlySpeed(double speed) from ScriptNpc.