Create API for import to facilitate batch import

1. Write and commit the API function definitions: (all functions will take in an array and return an array, the below is to illustrate what the functions do)

civicrm_import_create_table( $fileName );
civicrm_import_import_rows( $tableName, $offset, $limit, $params )
civicrm_import_delete_table( $tableName );
civicrm_import_create_mapping( $params );

2. Write a set of unit tests that utilize the above functions to verify that import works and creates the right contacts

3. Implement the functions that the unit tests can run against

4. Write a set of unit tests to test scalability