Draws a color-gradient beginning from fg and
if either fg_middle or fg_end is set, through them.
example config:
graph gr_cpu
{
data { scale = false max = 100 style = bottom
fg = "#cc6666" fg_half = "#cc6666" fg_full = "#998888"}
...
...
}
Signed-off-by: Julien Danjou <julien@danjou.info>