No more preprocessor directive in the file.

This is not very useful, now that there is the test on
`write_cont_list`. The test on `write_cont_list` should not be a
performance penalty.

Since we now have speed in the shapefile `cont_list`.

Move output of `cont_list` from `set_contours` to `set_max_speed`. The
advantage is that we will be able to add the speed to the shapefile.

Split dummy argument `e` of `set_max_speed` into relevant components.
Motivation: make appear clearly input and output.

Bug fix: manage absence of a good contour within the outermost
contour.

Move assignment to `e%max_speed` out of the alternative, to make it
just a little clearer.

Only for program `test_set_max_speed`.

Because we are going to add a preprocessor directive.

Complete the SSH sampling between `innermost_level_2` and
`outermost_contour`, and find associated contours in `set_max_speed`.

From `set_all_contours`, pass `n_cont` and the whole array `cont_list`
to `set_max_speed`, because we are going to define new elements into
this array in `set_max_speed`. `cont_list` in `set_max_speed` becomes
`intent(inout)`.

Because `cont_list` is going to become `intent(inout)`.

We keep ssh because we will need it if we call `good_contour`.

Remove dummy argument `ind_targ_extr` of procedure `set_max_speed`,
not used any longer.

Remove component radius4 of derived type eddy and field radius4 of
`outermost_contour.dbf`. They are not used any longer.

Abandon the radius4 approach, because the resulting max-speed contours
had speeds significantly lower than those from Matlab and because the
approach with radius4 is difficult to extend to a non
longitude-latitude grid.

Remove argument `outside_points` of `set_max_speed`.

Check we find a max-speed contour when `e%radius4 >= 2` and
`e%speed_cont%ssh /= missing_ssh`. See test `Set_max_speed_degenerate`
for a case when we do not find one.

Also split the tests, Fortran source files, Python files and JSon
files. Keep at the top level the files used in both `Inst_eddies` and
Overlap.

Motivations for the split:

- The top directory contained many files.

- It may be useful to compile only one of the two sub-projects. For
example, only `Inst_eddies` on Ciclad, where MPI 3 is not available.