Keep compat with old format if the SSID includes unprintable
characters. But having to type an int list for an SSID is just silly
and it's about damn time we fix that.
Clean up handling of "special" keys in keyfiles, ie ones that
need more processing than the basic GKeyFile API supports. Add
MAC address reading (writing support to come).
Additionally, add some test bits for the keyfile plugin that get
run on 'make check'.
