Changing default near plane position of perspective camera:

* By default perspective camera is setup so that projection on plane z=0 matches desired bounds 2d bounds. e.g. (0,0, w, h)
* But perspective projection suffers from z-buffer imprecision for objects that are far away from the near plane
* By bringing the near plane closer to z=0 we increase the accuracy of the projection at z=0 and in particular the calculation of the visible bounds