Georinex

* add ability to overwrite .nc files with "overwrite=True"
* make Rinex3 files handle INRSS
* add more header parameters
* make SP3 reading much more robust
* tolerate blank lines starting rinex file (default up to 10)
* use "unlzw3" for pure Python .Z files
* general test / CI / coverage improvements

* NAV3: allow multiple entries at same time, instead of discarding them as previous versions did
* fix allows Pandas >= 0.25 to be used, there was a bug where pandas 0.25 starting outputting dtype('O') that broke xarray.to_netcdf()
* OBS2: allow more flexibility where the RINEX file specifies the wrong number of observation types. This isn't foolproof, but at least tries to allow these RINEX files with incorrect headers.

thanks nmayorov 47

* add .sp3 SP3-C file reading
* add 'interval' metadata to xarray.Dataset output, if available in source data file.

For better reliability and ease of use, auto-build Hatanaka CRINEX inline converter program by discovering C compiler and compiling automatically when needed.

Move CI to GitHub Actions

** Restricts Pandas < 0.25.0 for the moment as Pandas 0.25.0 disallows writing NetCDF .nc files due to a conflict with xarray and datetime64[ns] inline conversion. Would have been tricky to discover without periodic CI.

v.1.11.0
created georinex/{geo,plots_geo}.py

BUGFIX: workaround bad lines in NAV3 files, filling those rows with NaN.

Ignore NAV3 fields "spare" and "FitInterval" which are missing and malformed in many NAV3 files.

Check number of times in file to see if it's as expected.