Gnssrefl

I have made good faith effort to institute the requirement for earthscope logins.
I had to change rinex 2.11, rinex 3, and highrate rinex 2.11 file downloads in both
rinex2snr and download_rinex. We will know on March 31 if I was successful.

I fixed a bug in gnssir triggered by unphysical elevation angles in NMEA messages
They peg at the same value - which makes LSP think that they have a window length
of zero. A warning is sent to the screen (if screenstats is set to True) and the satellite is skipped.

README.md now directs users to readthedocs.

added unavco2 option to test new unavco download protocols
requires earthscope-sdk import
currently works - I believe - for RINEX 2.11
users will need an account with Earthscope. [For more information on this](warning.md)

Made minor changes to subdaily. outlier file is created on the second go-thru, e.g.

Added alaska CORS sites if using the jeff archive.

added a few option to quickplt (mostly label axes)

Made a new option for snowdepth. Azimuth dependent bare soil correction is now
the default.

Changed RHdot calculation in subdaily to default behavior.

Added rt_rinex3_snr to allow real-time rinex3 generated files

Fixed various documentation pages.

Docker is refusing to build with these libraries.
Adding test version of refl_zones that looks for blocking signal azimuths.
Requires adding geopandas, xarray, and rioxarray. This module is current undocumented.

Fixed minor bug in refl_zones that did not properly act on information from UNR
database query.

Accommodated CDDIS file structure change for MGEX orbits.