Nintastic long version

This is my remix of the beautiful Nintastic case for the Raspberry Pi. The main difference is that the whole case has been made longer in order to make it possible to close the front door when there's a memory card in the Pi.

Other small modifications include, for the bottom part:
- Several of the thinner parts made thicker and stronger (I broke mine off on the original)
- Additional horizontal struts added on the parts supporting the Pi
- The USB and audio ports enlarged to allow