[MAP] Modified the disposals room to have a crusher and a stacking machine

It will allow the crew to recycle garbage.

![](http://i.imgur.com/fIprTZp.png)

 * Made conveyor belts invertable, to allow you to use corner pieces that are only intended for going backwards or forwards.
 * Added a new variable for disposal outlets which let you change their throw range. Default is 2 now.
 * The crusher can now be used by a screwdriver to de-emag it.