Added 3-d Rendering of tree to main generation

Rendering requires GLUT to work.
If you want to run the program without rendering the tree, simply remove
#include "TreeRender.h" and the code in main(), starting at "Begin 3-d
render code" and ending at "End 3-d render code" (In "Tree generation
test.cpp").

Additional Changes:
in "Tree generation.h" replaced "or" statements with the more common
"||"