SConstruct : Add freetype as GafferImage dependency.
SConstruct : Add freetype as GafferImage dependency.

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