Fixed some field definitions for FEC format version 5.1.
Fixed some field definitions for FEC format version 5.1.

This fixes SA, SB, and F3X record types.  There are other record types that are
probably still wrong.

ferranti/watchdog,MjAbuz/watchdog,aaronsw/watchdog,MjAbuz/watchdog,ferranti/watchdog,ferranti/watchdog,MjAbuz/watchdog,MjAbuz/watchdog,aaronsw/watchdog,ferranti/watchdog,aaronsw/watchdog