Bumping to Houdini Version: 13.0.568
Houdini Engine Version: 1.8 (API: 18)
Clean up some template types
Add color sets support for input mesh

The "current" color set will mapped to the "Cd" and "Alpha" attributes.
Other color sets will be mapped to attributes that are named after each
color set. For example, the "colorSet2" color set will be mapped to the
"colorSet2" and "colorSet2Alpha" attributes.