Change Bullet collision function name to make more sense. Implement collision radius property with a default value when unspecified, and allow setting to custom values individually from the size of the monster. Release Build 9272.
//NOTE: Marking a monster for deletion does not trigger any death events. It just simply removes the monster from the field!!
// The way this works is that monsters marked for deletion will cause the monster update loop to detect there's at least one or more monsters that must be deleted and will call erase_if on the list at the end of the iteration loop.