Gnssrefl

Changed default RH max in quickLook to 8 meters.

Multiple azimuth regions allowed in refl_zones. Documentation updated.

Require RH constraints (set in make_json_input or by hand) and then invoked
by gnssir **must** be at least 5 meters apart. These are used for the periodogram
and for quality control. Sometimes people think this setting is only for outliers. Outliers can still be
removed in **subdaily** with RH constraints. For now I am going to continue allowing this kind of
constraint in **quickLook**, but eventually I may remove it there too.

Changed make_json_input default max RH to 8 meters. Slight change to peak2noise default.
The first change will make peak2noise stats higher in general.

Added reflector height plot in subdaily that shows the results with respect to
azimuth. Should hopefully make it easier to track down azimuth issues for a mask.

Upon request, subdaily writes out evenly sampled RH values for the last spline fit.

Add newest L2C transmitting GPS satellite, PRN 28. Transmitting since January 31, 2023.
I do not believe it is healthy.

y-axis limits are now the same in quickLook periodograms.

Add L1C (I think) to rinex3 reading code - but it is a backup signal to default L1 C/A (S1C).
But I would really need to see more receivers to see what is going on here. They all seem to
use different settings.

Fixed persistent bugs that occur when trying to use gnssir to isolate problems with one satellite.
Now checks that the requested satellite is available on the requested frequency.
If not, it exits gracefully instead of crashing. This is when using -sat option, which is not
relevant for routine processing.

Allow capital letter station names in quickLook and gnssir (mac does not distinguish
between these two cases, but other machines do).

Explicitly check that people are not using illegal frequencies when they run gnssir

Fix bugs in nmea2snr related to how directories were created and discontinued numpy libraries

Updated snowdepth to have user-friendler bare soil definitions.

Added initial snowdepth utility.

removed np.float and np.int from gps.py library (no longer defined in newer numpy versions)