10.11.2 App crash on close and re-open

[Blair Neal]

Device will work fine when initially loaded by an app. If you close the application and then re-open it - it immediately crashes and points to not being able to receive data from the sensor. Requires you to unplug and re-connect the sensor to get the application to load it again. Close is being called properly - this was not occurring in 10.10 with Xcode 6, so it may be 10.11 or Xcode 7 - we also had a prototype unit, so some of the serial communication will be updated for the final production unit.