Add Wellcome data converter script.
Fix importing rows with no country.
Fix unicode compatibility in Django model str()
Add missing field name mappings (friendly to internal name).

These will appear in some standards-compliant files for import, even if
Indigo data doesn't currently include them.
Don't fail when importing a file with missing columns.
Django-import-export just fixed NullBooleanField.
Test that we can import entire Indigo dataset without errors.
Test that we can import converted Wellcome data.

Fix the date formats in converted Wellcome data.
Fix Wellcome importer to handle the 2000 and 2007 data.

The columns in the spreadsheets changed a few times over the years.
Add Nominet importer and tests.