Added start of frame detection for HUD data In the previous impmenentation the reception and evaluation of 15 byte were used without start detection. As a result sensor data could be stuck in case the frame sequence does not match the structure (e.g. cause by an framing error). To resolve this in case of an invalid checksumme in combination with a data lost detection a byte based reception is startet to detect the start of a frame using the break between two transmissions. In addition a babbling idiot protecting has been added because a faulty hardware could have an impact on the OSTC operation (high interrupt load)

Heinrichs Weikamp OSTC4 update files.

The builds are for testing purposes only. Be careful, they might not work and are definitely not recommended for real dives.