Stdin to Input. Two input dir provided for in tests.json: $input_dir
and $large_input_dir.

Rename everywhere variable nearby_extr to outside_points to avoid
confusion with function nearby_extr. Rename file "nearby_extr.csv" to
"outside_points.csv".

In procedure nearby_extr, include in the selection extrema with
different sign, even if they do not have sufficient amplitude.

Bug fix in read_eddy: use the value of read attribute to define
e%interpolated.

namelist input. Also, choose name of primary NetCDF variable in
namelist and read only this variable, not its coordinates. This makes
it easier to use an arbitrary NetCDF file.

In program test_set_outermost_contour, it is hard to remember the
order of positional arguments so we rather use fixed input file names
and no arguments.

In JSON input file for tests, it is simpler to use the "input" key
than creating a one-line input file, in some cases.