fixes:
- reduced number of threads to avoid issues on some hosting services ("OutOfMemoryError: unable to create native thread")
- fixed wrong position of solid "hitbox" with "furniture_sit" based on "item_frame" entity and 1x1 hitbox
- fixed wrong sit rotation with "furniture_sit" based on "item_frame" entity
- fixed "fixed_rotation" and "opposite_diretion" not working correctly when placing item_frame furnitures on walls
- added a check if /iazip command is called while another /iazip command is still processing