Fixed GafferScene TypeIds comments.
Fixed GafferScene TypeIds comments.

They had marked a perfectly valid TypeId as available for reuse, and lost the information about the history of obsolete TypeIds.

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