In commit d5e89eb9, the test was added with the useless key
"input". Now, after commit 29c37646, the useless key is the key "required".

Now that `inst_eddies` reads `main_nml` only on the first date, we do
not need to create a file `main_nml.txt` before running
`inst_eddies.py`. `inst_eddies.py` can just read `main_nml` from
standard input.

If we are appending to an existing SHPC then read `main_nml` from file
`used_nml.txt` instead of from standard input, and do not re-create
file `used_nml.txt`. It would be a mess to have an SHPC made with
different run parameters for different parts of the shapefiles.

Preparing to add exist as an argument of config.

Move the call to `find_package` for EZMPI to
`Overlap/CMakeLists.txt`. We are reverting in part commit f04aea8b
since `test_set_max_speed` no longer uses MPI.

Thanks to commit 5ff9e1d2, we are reverting in part commit f04aea8b.

Rename component `number_vis_extr` of derived type snapshot to
`number_extr`. Since there is no longer another compoment including
interpolated eddies.

Replace `SHPC_(anti|cyclo)_all_dates` by `SHPC_(anti|cyclo)`.

Otherwise the Fortran executable itself appends to `ishape_last.txt`.

(Writing times when the Fortran executable did not run was justified
by the existence of `elapsed_cat`.)

Create `SHPC_{orient}` before the loop on dates.

Since the program `inst_eddies` now directly appends to shapefiles.

So pass argument hshpc instead of `n_shapes`. Preparing to append to
`ishape_last.txt` instead of just creating `ishape_last.txt` with a
single line.

Preparing for using hshpc as argument of `write_aux`.

hshp would be the handle for a shapefile.

Read `days_1950` and `eddy_index` from outermost and max-speed
shapefiles. When we only opened shapefiles in reading mode, we never
needed these fields. It was enough to read the date and eddy index
from the extremum shapefile. But when we open in appending mode, we
need all the fields.

Because now there is a case when we want to open in appending mode: in
program `inst_eddies`.

Note that programs `test_max_speed_contour_ssh` and `test_weight`
depend on fortranGIS through the module derived_types. Compilation
worked without linking to fortranGIS because objects used by
`test_max_speed_contour_ssh` and `test_weight` in
derived types do not use fortranGIS.

Thanks to commit 5ff9e1d2, we are reverting in part commit 83123e30.

Thanks to commit 5ff9e1d2, we are reverting in part commits e1aa5bcc and
338dd393.

Thanks to commit 5ff9e1d2, we are reverting in part commit e1aa5bcc.

Than ks to commit 5ff9e1d2, we are reverting in part commits e1aa5bcc and
fda1e6cd.

Better to see a single label than several labels at the same position.

Instead of creating them. Motivation: avoid time spent concatenating
shapefiles in `inst_eddies.py`. This concatenation time, on Ciclad, is
of the same order of magnitude as the time spent by the Fortran
executable.

Motivation: we want to call `open_shpc` and `read_field_indices` from
program `inst_eddies` without making it an MPI program for one process only.

Because we are going to add preprocessor directives.

Change path from `Overlap/Analysis` to Analysis, following commit
3e41a613.

The program `test_write_overlap` was removed in commit c440ce20.

I added assert in commit 83123e30, I do not know why, it was not used.