doc: Fit the graph in 80 cols

Some man pagers do not reflow the text/graphs on resize
and the graphs did not fit the traditional 80cols due
the pod2man excessive indent.
log: Support for 256color terminals

And provide extended coloring capabilities for debugging.
The default colors do not change in 256 more to keep
supporting people using Black on White, White on Black and
Solarized terminals.

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>