because the order is not obvious.

In test_mean_speed and test_set_max_speed, do not read primary
variables with nf95_gw_var so the primary variables are allowed to
have or not a degenerate dimension.

low-amplitude threshold, min_amp.

Add component suff_amp to derived type eddy. Write this component in
extremum_$m.dbf.

In shapefiles, write positions of vertices in degrees rather than
radians.

test_get_snapshot reads the whole domain of input NetCDF files instead
of selecting a window through a namelist. This is clearer and more
convenient. Same in test_get_snapshot.py, test_local_extrema and
test_local_extrema.py.

In test_get_snapshot.py, annotate extrema instead of inserting a
legend.

More correct names: radian_per_degree to deg_over_rad,
degree_per_radian to rad_over_deg.

test_good_contour has more general input.

test_inside tests only inside, no loop on radius.

procedure get_eddy), with corresponding test.

Take into account the fact that derived type polygon became polyline
in library Contour_531.

Use new procedure null_polyline from library Contour_531.

Correct a sneaky bug in mean_speed: the last point in the polygon
array is a duplicate of the first point, do not take the last point
into account when averaging (and interpolating). Discovered this bug
because the mean speed was not exactly the same for equivalent
polygons with circular permutation.

Change philosophy for the tests: read whole NetCDF variables, prepare
different NetCDF files for different geographical regions if needed;
read all data from file or namelist; read names of files on command
line.

Use generic test_program.sh (which is out of this project) instead of
the specific tests_detection_eddies.sh.

test_set_outermost_contour are in degrees.