Renamed bright, high-contrast, and muted color palettes and add others

[pnkraemer]

All colour palettes that were taken from Paul Tol's website are renamed:

• bright -> paultol_bright
• high_contrast -> paultol_high_contrast
• muted -> paultol_muted

This breaks the existing code. Why is it a good idea?

1. So they are grouped together in the documentation
2. To avoid future confusion with other (e.g.) high-contrast palettes
3. To give more credit to the original author.

Additional palettes (medium-contrast, vibrant, light) have been added.

The pylint- and sphinx-configurations have been updated because they failed with the most recent versions.