[Catalyst] Some more FastCGI improvements

[Andy Grundman]

I'm intending to run some apps using external FastCGI processes so they 
can be restarted as needed without interrupting the web server.

So a couple things need to be added to the FastCGI engine.

Sam, I'm not sure why you only have ProcManager run if nproc > 1.  I 
think running it with even 1 proc is a good thing, because you can HUP 
the manager process to restart your application.  Do you see any harm in 
always running ProcManager when -listen is specified?

I also want to add a written pidfile for scripting purposes, and figure 
out how to get it to detach from the console.  Pidfile was easy:

     if ( $options->{pidfile} ) {
         $proc_manager->pm_write_pid_file( $options->{pidfile} );
     }

Do you have any ideas about how to get it to do a proper detach?

-Andy