These OSC commands report the default foreground and background colors.
Most terminals return the RGB components scaled up to 16-bit components, because some
legacy software are unable to read 8-bit components. The PR follows this conventions.
iTerm2 allow 8-bit reporting through a config option, and a similar option is
added here. In addition to picking between scaled and unscaled reporting, the user
can also turn off OSC 10/11 replies altogether.
Scaling is essentially c / 1 * 65535, where c is the 8-bit component, and reporting
is left-padded with zeros if necessary. This format appears to stem from the XParseColor
format.
