Custom Shoes::App#inspect to fix memory eating/crashes fixes #504

* BasicObject#method_missing raises a name error with the method
  name and it calls inspect on self.
* inspect calls inspect recursively on ALL of its instance vars
* the shoes app is kind of our object root and there is a lot
  of circular dependencies etc. going... therefore trying to
  create the inspect String (and putting it out) seems to eat
  SO MUCH memory that JVM crashes/errors with you are over the
  memory limit
* might be worth to write a custom inspect method for other heavy
  classes like the InternalApp, Slot, SlotContents
* Thanks to @KCErb for helping enormoysly with this