Support for javascript to return arrays to Java

Change notes:
- This uses existing Java code to create Java objects instead
  of doing it in custom code.
  The reason is existing code already sucessfully deals with
  arrays. Also creating java objects in C is prone to errors/crashes.

Change-Id: I8eb6823f5694037da4073ba15988c6325f1fb7f8
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>