Change update rate to 5Hz for testing.
Only update observation view when we have a full set of observations.

Reduces flicker in the display.
Removing dd experiments, will be moved into an experimental branch.
Cleaning up in track.c
Rename sbp_messages -> sbp_piksi and include sbp_messages from libswiftnav.

sbp_piksi will eventually just define Piksi specific messages.
Updating to latest libswiftnav.
Change default settings back to NMEA on UARTA and update the message mask for 16 bit types.
Update main.c and console to use new standard SBP messages for position/velocity/time.