v5.3.1 - Support VI firmware v6.x output format, better Bluetooth support

v5.3.1

• Improve reliability of automatic Bluetooth device detection and decrease the
  impact on battery life.
• Listen for Bluetooth VIs that initiate a new connection to avoid polling.
  Uncheck the "use polling" option in the Enabler if you have a new Ford
  Reference VI with a big "OpenXC" sticker on it, as this version is capable of
  initiating the Bluetooth connection on wakeup.

v5.3

• Automatically discover, initiate pairing and connect to Bluetooth-enabled
  OpenXC vehicle interfaces.