Added support for the "light" color prefix (in addition to "bright").

Added support for the "light" color prefix (in addition to "bright").

At the same time, restrict the advance by 8 to colors in the range 0-7
and no longer use the blink attribute to emulate light background colors
in some terminals (e.g. linux console and rxvt), as this is really blink
in other terminals (e.g. xterm); light background colors can still be
obtained by choosing a proper $TERM value (tested with linux console,
using TERM=linux-16color, and rxvt).