Megizen

- New player inputs event, helps detect what inputs players are pressing. - New MegActiveModel.dismount_passenger mechanism, which dismounts any given passenger mounted on an active model. - New MegActiveModel.dismount_rider mechanism, which dismounts any given mounted individual on an active model. - New MegModeledEntity.velocity tag, which returns the velocity of the modeled entity. - New MegModeledEntity.add_velocity mechanism, which adds velocity to the modeled entity. - New MegModeledEntity.global_move mechanism, which moves the modeled entity using the world axis, not respecting yaw/pitch. - New MegModeledEntity.move mechanism, which moves the modeled entity to the input vector, respecting yaw/pitch. - New MegModeledEntity.velocity mechanism, which sets the velocity of the modeled entity. - Minor cleanup