Add QColor support to v4.

Change-Id: I033e92007f894d45695ea48d7f954d534a2fadee
Reviewed-by: Chris Adams <christopher.adams@nokia.com>
Reviewed-by: Matthew Vogt <matthew.vogt@nokia.com>
Reviewed-by: Martin Jones <martin.jones@nokia.com>
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>