Fix clickable area when opening price breakdown

Once a price breakdown has been opened, the nub was over the bottom half
of the pie button. It made half of the pie unclickable.

And when you closed the breakdown, it became invisible but stayed
present, absorbing all clicks in that area. So other pie buttons were
unclickable as well.

app/assets/javascripts/templates/price_breakdown.html.haml

@@ -1,6 +1,6 @@
-.joyride-tip-guide.price_breakdown{"ng-class" => "{ in: tt_isOpen, fade: tt_animation }"}
+.joyride-tip-guide.price_breakdown{ng: {class: "{ in: tt_isOpen, fade: tt_animation }", show: "tt_isOpen"}}
   %span.joyride-nub.top
-  .background{ng: {show: "tt_isOpen", click: "tt_isOpen = false"}}
+  .background{ng: {click: "tt_isOpen = false"}}
   .joyride-content-wrapper
     %ul
       %li

app/assets/stylesheets/darkswarm/_shop-popovers.scss

@@ -25,6 +25,7 @@
 
   .joyride-nub.top {
     left: 7.4rem;
+    z-index: -1;
   }
 
   .background {