Feature/iconch

[pmaciel]

Description

Updated version that works with

eckit branch feature/eckit-geo (ready to be merged to develop)
eccodes branch develop
mir branch develop

There is quite an overlap with the Grid concept, although it is "clean" as far as it comes from eckit.geo.Grid.

Contributor Declaration

By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

[sandorkertesz]

Should we set a minimum version?