Fixes to support a wider range of field kinds
- Rename api.checkvalue() to api.checkValue() and swap argument order for consistency
- Add kind argument to api.checkValue() to identify which segment is being tested
- Limit wildcard test in remove() to string values
- Return error message from field.new() instead of raising error internally

--HG--
extra : rebase_source : 295534137f32d9af102e6c6c6bcabb7a856f257f