Blender Git Loki

Clipping of imported meshes by the near and far view planes.
A straightforward clipping algorithm was implemented to
eliminate vertices that are out of the interval from the
near to far clipping distance defined by the active camera.
Previously, objects that come behind the camera could lead
to a crash. The changes in this commit is intended to
address this issue. When meshes are partially clipped, new
edges are added. These edges can result in visible strokes
if they are within the camera view.