Optional colorized output for daemon process and ability to squelch log prefixes

Added a -color command line flag to enable coloring of daemon output success/failure messages. Currently this adds another dependency on github.com/fatih/color . If you'd rather not have another dependency, I'd be happy to pull out just the parts of that library that are used in this pull request.

I also added a -log-prefix flag to control whether or not the output from the daemon includes log timestamps and the "stderr:"/"stdout:" labels. When combined with colorized output from the daemon process, I find that having additional logging info just pollutes the output.

Both of these new options are set to defaults that keep the existing behavior of CompileDaemon functioning as normal.