HPCC-10150 Add support for relative imports using $.^.^.X

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-10150 Clean up and add examples following code review.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>