Invalid Gtk 3 Properties

[samlitowitz]

Some Gtk 3 properties are improperly set resulting in errors such as the following.

(unity-tweak-tool:18347): Gtk-WARNING **: 11:11:27.380: Theme parsing error: gtk.css:2525:61: '-1px' is not a valid color name

(unity-tweak-tool:18347): Gtk-WARNING **: 11:11:27.380: Theme parsing error: gtk.css:2531:35: '-3px' is not a valid color name

(unity-tweak-tool:18347): Gtk-WARNING **: 11:11:27.383: Theme parsing error: gtk.css:4362:30: '-2px' is not a valid color name

(unity-tweak-tool:18347): Gtk-WARNING **: 11:11:54.154: Theme parsing error: gtk.css:2531:35: '-3px' is not a valid color name

(unity-tweak-tool:18347): Gtk-WARNING **: 11:11:54.155: Theme parsing error: gtk.css:4362:30: '-2px' is not a valid color name

(unity-tweak-tool:18347): Gtk-CRITICAL **: 11:12:52.661: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkNotebook

(unity-tweak-tool:18347): Gtk-CRITICAL **: 11:12:52.661: gtk_box_gadget_distribute: assertion 'size >= 0' failed in GtkNotebook