Incorrect value for auto-gain

Incorrect value for auto-gain option the Modes.gain is multiplied by 10.
Merge pull request #16 from papasven/master

Incorrect value for auto-gain
Merge branch 'master' of https://www.github.com/MalcolmRobb/dump1090
B"H allow disable ports, doc disable net heartbeat
Merge branch 'network_disabling'