Allow popsicle stick animations on rigged meshes.
Allow popsicle stick animations on rigged meshes.

Popsicle stick animations are those with only one bone.
They can animate any mesh by applied their transform
to the root of the mesh.

We now allow meshes with many bones (that is, rigged meshes)
to accept popsicle stick animations.

Change-Id: Ic5d93dd3b5e01481efb1891bea8baf1c2e9ea54c
Tested: Works in sample game on Linux.

google/corgi,google/corgi