RTCM: prepare a series of experiments to determine whether any of the correction sources are missing a factor
RTCM: More experiments regarding the correction inclusions

It appears as though the observations from the NTRIP stations aren't corrected for their
own receiver clock bias which is really strange.  Or at least, this correction has the
equivalent of 12 metres of error.
RTCM: Add option to force NTRIP rx clock error to zero

This is done by estimating the clock error by lsq then subtracting
that from the PRs before transmission.  If enabled, a second lsq
run is done after correction to ensure that it has in fact worked
(mainly a debugging thing)
positionEstimate: Move rx clock estimation in from RTCM code

This will allow its use for the local corrections as well
RTCMv2: Fix an occasional key error for sats with partial ephemeris
Local: Solve for clock err using reference pos if available

Previously we did a full 4D solve even if the spacial dimensions were known.
This now means we're only optimizing over one variable and should get better accuracy
Remove a few data files from VCS
Errlog: Add XY plane plot by default