- Naming: sqlite3ErrName => pysqlite_error_name
- Error handling:
    * return NULL if no exception matched
    * receiver handles errors
    * don't use error table to store SQLITE_UNKNOWN string

- Use intermingled declarations
- Simplify ref count handling

- Declutter add_error_constants()
- No need to typedef struct
- Simplify naming
- Use PyModule_AddIntConstant

To avoid mismatch between char *name and constant

IMO, we should not pollute the SQLITE_* namespace

- Use correct attribute name
- Normalise error variable naming
- Remove 'Errno' from printed string to avoid confusion

- Use assertRaisesRegex iso. two assert functions
- Normalise quotes
- Test that constants are added to the module

…ability