Change default palette to a dict

The list was unnecessary, and it made it harder to copy-paste entries to
specific themes.
Make the command line button a different color in the theme

Change the color to something more reasonable in the midnight theme.
Merge branch 'master' into button_color
Add note to example-theme.py about curses and raw modes
Merge pull request #100 from asmeurer/button_color

Update command line button colors (as discussed on the list)