Blender Git Loki

BKE_mesh_new_from_object(): do not generate temp obj/cu in Main.

When generating a mesh from a curve object, do not generate temp objects
and curves in main, but rather as 'localized' copies.

This is cleaner, and might add a marginal speed-up in some cases (like
rendering thousands of curve objects), since we save some processing.
Note that this is the function behind py API's `Object.to_mesh()` too.