Pyjams

* Merged old library JAMS (https://github.com/mcuntz/jams_python) as a
subdirectory. Remove deprecated routines that are in the main part now.
Remove unsupported routines.

* Set filename without suffix as default plot name in `mcPlot`.
* Exit if initial population failed twice in `sce`.
* Allow ncol=1 in `color.get_cmap`.
* prepend and append keywords in `mad`.
* Warn only if lb > ub, simply set mask if lb == ub in `sce`.
* Add functions `pack`, `unpack` mimicking Fortran intrinsics.

* Replace plotly with hvplot in `mcPlot`.
* Add unicode symbol degree \u00B0, which gets replaced by ^\circ
if usetex==True in str2tex.
* Do not escape % if not usetex in str2tex.
* Make `get_variable_definition` public in ncio.
* Correct docstring of strip keyword in fsread and xread.
* Added `filebase` to helpers.
* Exchanged functions and wrapper functions in readnetcdf.

* Added functions `eair2rhair`, `rhair2eair`, `eair2vpd`, `vpd2eair`,
`rhair2vpd`, `vpd2rhair`, `eair2shair`, `shair2eair`, `eair2mrair`,
`mrair2eair`, for conversions between partial pressure, relative humidity,
and specific humidity of water vapour in air.
* Renamed module `esat` to `air_humidity`.
* Correct treating of undef if two arrays given in `array2input` helper
function.
* Updated all constants related to gases in `const` module for redefinition
of SI units of 2019.
* Renamed some constants in `const` for greater consistency.
* Keyword only_use_pyjams_datetimes in `num2date` to be able to use all
implemented methods of `datetime` class.
* Allow also CF-calendars in `datetime` class.
* Updated tests for `sce`.

* Add `updatez` and `updatez_compressed` to update arrays in a single file
in numpy's npz format.
* Do not set color for missing data; only existed for sron palettes.
* Add --dpi as a standard option in `mcPlot`.
* Use mpl.colormaps[name] instead of mpl.colormaps.get_cmap(name)
to replace mpl.cm.get_cmap(name) to work with matplotlib < v3.6.

* Assure 4-digit years and catch %04Y format errors on Windows in
`date2date` and in datetime class.
* Use assert_almost_equal for fractional days with microseconds in tests of
datetime class
* Changed matplotlib.cm.get_cmap to matplotlib.colormaps.get_cmap in
color module and tests.
* Skip test for float128 on Windows in `ncio`.
* Python 3.6 might not be fully supported anymore.
* Remove dependency to ``partialwrap`` for tests.
* Adding `sce` the Shuffled-Complex-Evolution algorithm for function
minimization.
* Adding 'a wide variety of' to ``pyjams`` key phrase.
* NA to NaN, i.e. R to Python convention in `fsread`.