Blender Git Loki

Fix for a crash when freeing copied scenes.

The problem was caused by the fact that BKE_scene_copy() was simply doing "memcpy"
to duplicate render layers including lineset settings without taking care of pointers
in the linesets. For this reason, freeing the original scene and copied one resulted
in freeing allocated memory buffers twice.

Now BKE_scene_copy() properly duplicates linesets as part of render layers.

Also some code clean-up was made in the modified files.

Problem report by IRIE Shinsuke (with a patch to fix the crash). Many thanks!