[Gtk-3.20] Reduce menubar height to match gtk2 theme. Fixes #453

Author: megax

gtk-3.20/scss/widgets/_menu.scss

@@ -18,7 +18,7 @@
 
         > menuitem {
             min-height: 16px;
-            padding: $spacing ($spacing * 2);
+            padding: ($spacing - 1px) ($spacing - 1px) * 2;
             border: 1px solid transparent;
             background-color: transparent;
             background-image: none;
@@ -67,7 +67,7 @@
         menuitem {
             min-height: 16px;
             min-width: 40px;
-            padding: $spacing;
+            padding: $spacing - 1px;
             border-radius: 0;
 
             &:active, &:hover {