fixed broken detection of "unset" configuration settings.
the code was assuming that the first byte of each setting will be 0xff if it's unset but in testing i found this not to be the case.
testing for [a-zA-Z] isn't ideal but it seems to work. also hacked internval "set" state detection by testing for an integer between 500000 and 555555.
again, not ideal, but i'm only going to use round numbers so it's good enough.