Stop automatically triangulating imported objects.

I don't know why there's no option to NOT triangulate imported meshes, but it needs to be added. You're already allowing us to work in quads, so if I import a mesh that's already in quads, triangulating it automatically voids ALL OF THE WORK I PUT INTO IT! It's fine if you want it that way, but not giving us the option to keep the mesh as is does not make sense--especially since we can work in quads! These days, I find myself doing more work in Blender just because I hate the fact that MD always messes up my topology.