Rename `toxi.color` package due to P5 grammar rule changes

[postspectacular]

Processing v4 has updated parse grammar rules, which now are classifying color also as reserved keyword if used within a multipart, dot-separated package name and thus breaking any project which attempts to import toxi.color.*;. The P5 team seems to have marked this as working-as-intended, breaking 2 decades old existing behavior. Therefore, I will now have to rename this package to something similar and attempt to build a new release, incl. updated examples...

Proposals for the new package name are gladly accepted!

See relevant issues:

• https://github.com/processing/processing4/pull/246
• https://github.com/processing/processing4/issues/240