Implemented PathPlugValueWidget.setHighlighted().
Implemented PathPlugValueWidget.setHighlighted().

Now the main path widget is highlighted properly so it's obvious when drag and drop operations are afoot.

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