Updated change log.

    config/tutorial/tutorial.rc

Changes for v2.2

----------------

Option to create gridded fields from orbit files in listing.

  py/cso_gridded.py

  py/cso_file.py

  config/tutorial/tutorial.rc

Changes for v2.3

----------------

Added collection level to inquire overview plots.

  py/cso_inquire.py

Convert selected orbit files based on selection query.

  py/cso_s5p.py

Synchronized template settings for Copernicus S5P products.

  config/Copernicus/

Updated User guide.

  doc/source/

Changes for v2.4

----------------

Added 'black' target to Makefile, including convention for maximum line length.

Reformatted files following new convention.

  Makefile

  py/*

Changes for v2.5

----------------

Fixed definition of CSO_PREFIX environment variable.  

  bin/cso

Updated tutorial.

  config/tutorial/tutorial.rc

  doc/source/tutorial.rst

Define lon/lat axes of gridded output as floats.

  py/cso_gridded.py

Use pandas concat to combine dataframes.

  py/cso_pal.py

Replaced `where` concstructs by loops after memory errors in output filling.

  oper/src/cso_ncfile

Check on `pix_all` value to know if pixels are assigned to any of the sub-domains.

  src/tutorial_oper_S5p.F90