Implemented trapped chests & others

+ Added trapped chests
* Fixed a bunch of bugs in the redstone simulator concerning wires and
repeaters
* Other potential bugfixes

I hereby present to xoft, ONE METRIC TON PRECISELY -----------------
-------------------------------  of code to review.

With thanks.
In any case, have you tested this? It really looks to me that erasing while iterating the way that you did would invalidate the iterator and cause major issues.