Sample Scene: Fix Broken Links In Data Binding Sample Scene

[AMollis]

This issue has been migrated a new MRTK repository, and the status of this issue will now be tracked at the following location:

• Sample Scene: Fix Broken Links In Data Binding Sample Scene MixedRealityToolkit/MixedRealityToolkit-Unity#135

---

In the sample scene for theming and data binding, many of the images do not load due to 404 not found and failed to connect errors. These links should be replaced.

Additionally, there is a repeated error "Release of invalid GC handle. The handle is from a previous domain. The release operation is skipped." and several other errors when the scene is first run, which should be investigated.