made Parameters work with objects derived from Light/Camera/ExternalProcedural
made Parameters work with objects derived from Light/Camera/ExternalProcedural

johnhaddon/gaffer,johnhaddon/gaffer,chippey/gaffer,ImageEngine/gaffer,ImageEngine/gaffer,GafferHQ/gaffer,boberfly/gaffer,boberfly/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,goddardl/gaffer,ivanimanishi/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,chippey/gaffer,goddardl/gaffer,johnhaddon/gaffer,ivanimanishi/gaffer,lucienfostier/gaffer,appleseedhq/gaffer,boberfly/gaffer,appleseedhq/gaffer,hradec/gaffer,boberfly/gaffer,chippey/gaffer,hradec/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,goddardl/gaffer,andrewkaufman/gaffer,lucienfostier/gaffer,chippey/gaffer,hradec/gaffer,andrewkaufman/gaffer,lucienfostier/gaffer,andrewkaufman/gaffer,ivanimanishi/gaffer,andrewkaufman/gaffer,ImageEngine/gaffer,lucienfostier/gaffer,johnhaddon/gaffer,goddardl/gaffer,hradec/gaffer,hradec/gaffer,ivanimanishi/gaffer,ImageEngine/gaffer