Fixed a lot of small issues:
-Buttons do not crash game anymore if they are added without any defined moving boxes.
-buttons, power-ups and movingboxes can now be removed with the remove EditMode
-buttons in the maze dissappear if they would fall outside the maze after resizing.
-the height of the pit has been lowered to 20 instead of 100;
-Textures of custom objects in case of multiple different ones now work.
-Empty maze object added with name Empty: cannot be added to the maze yet.