Adding overrideTransform toggle which exposes the t,r,s parms.

This can be used to override animated transformations coming from the file with user specified transforms.
Reorganized SceneCache parms.

Moved Push button and all the options it effects to a new Options tab
Added attributeCopy option parm (used in next commits)
Pushing the attributeCopy parm when expanding SceneCache OBJs
Creating struct for SceneCacheSource parms to avoid function bloat
Using attributeCopy parm to modify the loaded object before converting to Houdini.
fixing spelling mistakes
Merge pull request #166 from andrewkaufman/transformOverride

Adding overrideTransform toggle which exposes the t,r,s parms.
Merge pull request #167 from andrewkaufman/pref

Houdini Attribute Copy for SceneCaches