[Bugfix]--Fix CatmullRom Traj off-by-ones; add multiple colorspaces gradient support

[jturner65]

Motivation and Context

This PR fixes a couple bugs with the CR spline trajectory tube calc. The precalculated distances to be used as knot values were being accessed off-by-one, and the time interpolant itself was never reaching t2.

This PR also introduces support for other color spaces to traverse for the trajectory gradient.

How Has This Been Tested

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[aclegg3]

LGTM, thanks for the rapid fix.