[Smtk-developers] PLY support and auxiliary geometry test data

[David Thompson]

Hi Jie,

I've added the files listed below to the test-data repo. The 4 shapes do not overlap, so your test can just load one shape for each file-format and a single screenshot will do.

Once [SMTK MR 655](https://gitlab.kitware.com/cmb/smtk/merge_requests/655) is merged, auxiliary geometry instances whose URLs point to PLY files will be rendered properly.

Also, I've merged in the fix for GrabCuts so now loading in a "lines" file will let you run immediately without further input.

	David


model/3d/obj/box.obj
model/3d/obj/cone.obj
model/3d/obj/cylinder.obj
model/3d/obj/sphere.obj
model/3d/ply/box.ply
model/3d/ply/cone.ply
model/3d/ply/cylinder.ply
model/3d/ply/sphere.ply
model/3d/vtk/box.vtp
model/3d/vtk/cone.vtp
model/3d/vtk/cylinder.vtp
model/3d/vtk/sphere.vtp
point_cloud/box.pts
point_cloud/cone.pts
point_cloud/cylinder.pts
point_cloud/sphere.pts