* plugins.d/mandos-client.c: An empty interface name now means to autodetect an interface; to specify no particular interface, use "none". (sys_class_net): New global variable for the "/sys/class/net" path. (good_interface): New function to determine the suitability of an interface. Used by a scandir() call in main(). (main): Changed default value for "interface" to the empty string. Moved "connect_to" to be a global variable. Only take down and up interface if its name is not "none". * plugins.d/mandos-client.xml (OPTIONS): Update documentation for the "--interface" option.