merge changes of version 1.3
The release includes the following changes:
- improved pressure handling
- dates are consistently named as local_dates or utc_date or meas_date
- web documantation with sphinx
- adaption to PROFFAST changes
- alternative CO2 from different spectral window
- new calibration
- new ILS list
- producd .spc files are moved or deleted (instead of ignored)
- different logging modi to use logger in case proffastpylot is included into a larger environment