Running average for course/speed

[bergie]

Right now we enter that moment's course, speed, and heading into the log. In bigger sea state these can vary a lot as the boat gets tossed around in waves. A running average of some short time (like 10-15sec) might help.

Suggested in https://forums.ybw.com/threads/your-vessel%E2%80%99s-log.614973/#post-8549862