Blender Git Loki

Add panels for the new planar tracker

This replaces the old style tracker configuration panel with the
new planar tracking panel. From a users perspective, this means:

- The old "tracking algorithm" picker is gone. There is only 1
algorithm now. We may revisit this later, but I would much
prefer to have only 1 algorithm. So far no optimization work
has been done so the speed is not there yet.

- There is now a dropdown to select the motion model. Choices:

* Translation
* Translation, rotation
* Translation, scale
* Translation, rotation, scale
* Affine (Not implemented yet)
* Perspective

The most stable is the "translation" parameterization. The
others work but still require some tweaking.

- The old "Hybrid" mode is gone; instead there is a toggle to
enable or disable translation-only tracker initialization. This
is the equivalent of the hyrbid mode before, but rewritten to work
with the new planar tracking modes.

- The pyramid levels setting is gone. At a future date, the planar
tracker will decide to use pyramids or not automatically. The
pyramid setting was ultimately a mistake; with the brute force
initialization it is unnecessary.