Fix multiple logs during BT NTRIP

Note: Release candidate binaries have additional debug messages turned on. Don't be alarmed if you see lots of additional serial output.

Note: If you are running firmware v3.x or greater, you can load the latest firmware or release candidate over the air. If you are using older firmware (2.x or lower) you will need to load v3.x firmware using a USB connection. We have created a Windows GUI to ease this process. Please see Updating Firmware from GUI for a step by step process.

Changes in this release:

• Bug #469 - Fix NMEA/UBX data corruptions and multiple log creation when sending RTCM over Bluetooth SPP