* guest#running?

* guest?, iface? (also Guest.include? resp. guest.include?)
 * easy accessors for guests and ifaces (Guest.sun instead of Guest["sun"] and guest.eth0 instead of guest["eth0"])
 * if a block is given for iface#add or iface#del then the change is only temporary while executing the block and gets reverted afterwards

src/dumm/guest.c

@@ -214,6 +214,7 @@ static void stop(private_guest_t *this, idle_function_t idle)
 			}
 		}
 		unlinkat(this->dir, PID_FILE, 0);
+		this->pid = 0;
 	}
 }