Update gtk2 theme

* Fix progressbar and scales background color
* Fix treeview separator color

gtk-2.0/links.fish

@@ -0,0 +1,13 @@
+set -l files 'checkbox' 'radio'
+set -l states 'unchecked' 'checked' 'mixed'
+set -l sub_states 'active' 'hover' 'insensitive'
+
+for f in $files;
+	for s in $states;
+		ln -sf ../../assets/$f-$s-dark.png ./assets/$f-$s.png
+		for i in $sub_states;
+			ln -sf ../../assets/$f-$s-$i-dark.png ./assets/$f-$s-$i.png
+		;end
+	;end
+
+;end