the *last* level 2 or 3 heading would be used as tab title instead of the first one.

i.e. trasform XYZ bytes to something readable

Allow `colorN' and `colourN' (where 0 <= N < 256) as color specifier.

`attr' now follows the same rule as `fg' and `bg', with the three airity variant. Attributes by themselves are a comma-separated list of keywords, each one representing a ncurses attribute.

currently unused, will help later when adding colour support