For legacy systems that do not support Metal. The Metal SceneKit view
does work on even 10.13.6, if a Metal GPU is present in the system.
Signed-off-by: Christopher Snowhill <kode54@gmail.com>
Improvement includes greatly reducing the CPU usage by not using an
NSImage based painting system.
Signed-off-by: Christopher Snowhill <kode54@gmail.com>