#78 Billboard objects might not be selectable.

[JukkaJ]

Create a box primitive some distance away behind the billboard, and scale it to cover the whole background of the billboard.
Try to select the billboard.

The selection always picks the box behind the billboard, and the billboard is impossible to be chosen.

Expected: The billboard should get selected instead.

Tested in server & client builds 20081118.

[JukkaJ]