Bad warning - No GPS data

[ghuotvez]

Related to #138, when the positionChanged event receives a NoData value, from the positionStatus enum, it shows a warning about flight mode being activate, then it forces the app go in tap mode.

Change this for a warning that says, couldn't get a position, will retry please wait or please be patient.

[ghuotvez]

There is a now a new message and a delay of 30 sec before each new messages, so the app has enough time to actually get a good GPS fix if it's the problem or let the user deactivate flight mode if this is the real problem.

There is no auto shut off of the GPS now when NoData is received, it'll try again for a new location.