VOXEDIT: ortho views are not working

[mgerhardy]

78e07a908e2ad1dedc00bc44f2d6f66f056baf67 activates the ortho camera views for left,right,top and bottom viewports.

The Camera::screenRay() or the SceneManager::trace() is broken for the ortho views.

Once the tracing is working we should not limit the ortho views to the 3 viewports as given in the above commit, but should add a viewport combobox with perspective, orthographic, isometric. to switch each camera between these modes. Stuff like position (eye, pan), rotation and zoom factors must be preserved of course.

Smooth transition between perspective and orthographic modes