No way to handle expected error situations

[EliRibble]

A number of H3 API endpoints return errors. For example, I'm building with gridDistance and the API docs indicate:

Note that finding the grid distance may fail for a few reasons:

• the cells are not comparable (different resolutions),
• the cells are too far apart, or
• the cells are separated by pentagonal distortion.

These states should be translated into errors that client code can deal with directly rather than through precondition

[EliRibble]

There are about 15 H3 error codes

[EliRibble]

Fix in #7