"Pastel (Dark Background)" from source, see previous commit.
Other palettes not imported:
- Tango Dark: the same as current tango (except black is 000000)
- Solarized Dark: entirely different scheme alternative to ansi colours;
based on <http://ethanschoonover.com/solarized> and similar to base16
<https://github.com/chriskempson/base16> with many compatible themes
comparable at <http://chriskempson.github.io/base16/>.