- In the middle of implementing RTree data structure to be used later
for ray intersection for pins.
 - tiny changes I wanted to save still working on RTrees
 - Added the way to mark where pins are. Currently there is a pin on
some arbitrary location. You can rotate the model to see how it becomes
more transparent as it's behind the model or more visible in the front.
 - Haven't tested RTree quite well yet, but it seems to build properly.
Merge branch 'develop' of ssh://git@github.com/ddksr/Raa3D.git into develop