Promote u and v to variables of module `input_ssh_m`, and remove them
as dummy arguments of `input_ssh`, `set_contours`, `mean_speed` and
`set_max_speed`. u and v are defined in procedure `input_ssh` and used
only in procedure `mean_speed`.

Remove dummy argument corner of function `mean_speed`, not used any
longer.

The case of u and v is different from the case of ssh. For ssh, we
want to restrict as much as possible the size of the array we work
with because we search all the contours in the corresponding
window. But for u and v, we only do a bilinear interpolation, without
a call to locate or hunt within the interpolation procedure, so there
is nothing to be gained to work on only a window of u and
v. Furthermore, we are preparing to allow staggering of the u and v
grid with respect to the ssh grid so if we wanted a window of u and v,
there would be the complication of choosing the window taking the
staggering into account.

It was not convenient to read them with input function or on the
command line: too much to read this way, and not clear when saved in
JSON text file. And we already had to create a namelist file
anyway. And this way the namelists can be extended transparently.

Instead of `config_nml.txt`. Preparing to include other namelists in
this file.

Bug fix: do not provide standard input for `inst_eddies_Aviso.py`, it
does not read it.

In the case of non-uniform longitude-latitude grid: we read the whole
coordinate arrays from the NetCDF file; we have a different way of
inverting the projection, in `invert_proj`; the program `eddy_graph`
does not use `corner_whole` and step, which are not defined, it uses
instead the shapefile `extr_proj`.

Preparing to generalize to a non-uniform longitude-latitude grid.

In program `test_mean_speed`. To make it work with a non-uniform grid,
we would have to read a contour in projection coordinates.

Use `uniform_lon_lat` from modules `input_ssh_m` or `read_grid_m` to
compute actual argument of `shpc_create`.

In program `examine_eddy`.

Replace dummy argument `grid_lon_lat` of procedure `shpc_create` by
`with_proj`.

Specify whether to read shapefile `extr_proj` in procedure `shpc_open`
instead of just trying to read this shapefile. Use `uniform_lon_lat`
to decide whether to read the shapefile. As `shpc_open` is called in
both programs `inst_eddies` and `eddy_graph`, we cannot access
variable `uniform_lon_lat` of module `input_ssh_m`, which is not used
in program `eddy_graph`, nor variable `uniform_lon_lat` of module
`read_grid_m`, which is not used in program `inst_eddies`. So we add a
dummy argument `with_proj` to procedure `shpc_open`.

Rename variable `corner` of module `input_ssh_m` to `corner_whole`.

I did not like the difference of treatment between corner and step.

Preparing to read a second input variable from stdin in procedure
`input_ssh`.

Instead of deducing it from the longitude coordinate. The deduction
could not be generalized to a non-uniform longitude-latitude
grid. Also, the test on `step(1)` and nlon was not perfectly robust.

We are trying to simplify the logic in program `inst_eddies`. Also,
the program `inst_eddies` should not write `grid_nml.txt` to the top
level of the SHPC directory since several instances could run in
parallel for several slices. So we are leaving it as a task for a
script above `inst_eddies` to create `grid_nml.txt` at the top level
of the SHPC directory. In tests, we have to move `grid_nml.txt` to
SHPC because we use `SHPC/grid_nml.txt` in other tests.

We are reverting commit d4d05bc2. It was not true that we needed two
input fluxes in the Fortran program. `inst_eddies.py` can read the
file `config_nml.txt` and merge its content to stdin for the Fortran
program.

Add argument SHPC-dir to script `inst_eddies_Aviso.py`. We want to be
able to run `inst_eddies_Aviso` in parallel for several slices. Since
we write `used_config_nml.txt` to the current directory, we need to
run the parallel instances from different directories. So the current
directory cannot always be the directory containing the SHPC to be
appended to.

Add argument `SHPC_dir` to function `loop_inst_eddies`. We want to be
able to run `loop_inst_eddies` in parallel for several slices. Since
we write `used_config_nml.txt` to the current directory, we need to
run the parallel instances from different directories. So the current
directory cannot always be the directory containing the SHPC to be
appended to.

We are trying to simplify the logic in program `inst_eddies`. Also,
the program `inst_eddies` should not write `used_config_nml.txt` to
the top level of the SHPC directory since several instances could run
in parallel for several slices. So we are leaving it as a task for a
script over `inst_eddies` to create `used_config_nml.txt` at the top
level of the SHPC directory.

We want to be able to run `inst_eddies` from a directory other than
the directory containing the SHPC to be appended to. Preparing to
write `grid_nml.txt` and `used_config_nml.txt` in the current
directory. To be able to do this in parallel for several slices, we
need to be running in different directories.

In program `examine_eddy`.

Change order of command line arguments of program
`examine_eddy`. Preparing to allow a variable number of NetCDF file
arguments.