Idl: allow a triplet output for forward declarations.
Idl: allow a triplet output for forward declarations.

Change-Id: Id57369771587f89d113d0755f9c40a0fd7bff299
Reviewed-on: http://gerrit.aldebaran.lan:8080/12535
Reviewed-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>
Tested-by: mnottale <e3ccf1b6558404e921a21fa09cebb1153b50ec36@aldebaran-robotics.com>

aldebaran/libqi,aldebaran/libqi,bsautron/libqi,vbarbaresi/libqi,aldebaran/libqi