daemon: Make daemon_init_colors_or_die() independent of gengetopt.

daemon: Make daemon_init_colors_or_die() independent of gengetopt.

The function receives the values given to the --log-color option as
a char * array, which is the type that gengetopt provides for the
arguments to string options which may be given multiple times.

This patch gets get rid of this implementation detail. The function no
longer takes the arguments to --log-color at all and applications now
must call daemon_set_log_color_or_die() themselves to set user-defined
per-loglevel colors.

To make this work, we let daemon_init_colors_or_die() return a
boolean which indicates whether color mode should be enabled, and
daemon_set_log_color_or_die() is made public. The two users of this
API, para_server and para_audiod, are adjusted accordingly.