Further cleanup, move signal setup to a file of its own.

finit.c:
        o Perform signal setup as soon as possible, no need to do any
          mounting of /proc or /sys beforehand
        o Move signal setup and callbacks to a file of its own
        o Use more #defines for hard coded strings
        o Use a more neutral default hostname

signal.c:
        o New file, for setup and signal handlers
        o Add support for SIGSTOP/SIGSTP and SIGCONT.  This pauses finit
          respawning of xinit/shell.  Useful for, e.g., debugging
        o Document each ignored and handled signal better
        o Disable SIGUSR1 and SIGUSR2 for now, will be reenabled later

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

initctl.c

@@ -72,10 +72,10 @@ void listen_initctl(void)
 			if (request.cmd == INIT_CMD_RUNLVL) {
 				switch (request.runlevel) {
 				case '0':
-					shutdown_handler(SIGUSR2);
+					do_shutdown(SIGUSR2);
 					break;
 				case '6':
-					shutdown_handler(SIGUSR1);
+					do_shutdown(SIGUSR1);
 				}
 			}
 		}