Texture 2D reload on src attribute change

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Test ring and circle meshes

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Sun mesh with Dart logo on it

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Add Saturn ring.

Signed-off-by: John McCutchan <john@johnmccutchan.com>