Add automated "do not log" modes to WIBL logger for certain users with privacy concerns

[selimnairb]

For some volunteers, it might be important to turn off logging when in certain states (for example, when not in transit). This could be due to privacy constraints, or other sensitivities. Ideally, however, this should be automatic, even if the volunteer gets to choose what conditions need to apply for logging to occur, since otherwise it would be too easy for the system to be turned off and never get turned on again.

For bonus points, the logger should demonstrate the logging/not logging status on the LED.