Adding things to quadtree is implemented but segfaulty.

Adding things to quadtree is implemented but segfaulty.

(i.e. it segfaults all of the time, and even if it didn't, it'd
crash if you zoomed in, and also you can still only add things to node 0
and really this breaks a lot more than it fixes)

For the prosecution, segfaults except:
- When run in valgrind
- When run in gdb on nvidia hardware

Infinite loops when:
- You zoom in, zoom out, add an object, and zoom in again.