Instead of several values of the handler dictionary. Clearer and more concise.

Instead of tuple. Preparing for extensions to return orientation and
to deal with several SHPC.

Using `ishape_last`, instead of iterating through the shapefile.

From directory Analysis. Extract corresponding tests from
`Analysis/tests.json` into new file `Inst_eddies/Analysis/tests.json`.

In script `eddy_dump.py`, do not assume that there is a single date
index. So find ishape by iterating through values of date index and
eddy index.

Add a test of overlap in `short_tests.json`.

Take into account new policy in `filter.py`: the names of the three
shapefiles are always the same and form a unit in a snaphot directory.

Rename `compil_prod_dir`to `build_dir` in JSON test files. Add a test
of `successive_overlap` with global grid, normal resolution.

Take into account new policy in `filter.py`: the names of the three
shapefiles are always the same and form a unit in a snaphot directory.

Rename `compil_prod_dir`to `build_dir` in JSON test files. Add a test
of `successive_overlap` with global grid, normal resolution.