Added "Delete" menu item to user plug context menu.
Added "Delete" menu item to user plug context menu.

Also slightly improved the layout for the + icon and added a tooltip.

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