Designed primarily for a graphical Vim, but includes support for 256, 88, 16,
and 8 color terminals. On a 16 or 8 color terminal, replace its colors with
ansi-term-colors.txt for best results.
If you can't change your terminal's colors, add
let g:jellybeans_use_lowcolor_black = 0 to your .vimrc to render
'black' text as grey.
This script is vimscript #2555 at Vim.org.