visual feedback in ceval bar while engine is computing

look ma, I'm doing design shit!

public/stylesheets/analyse.css

@@ -310,16 +310,24 @@ body.piece_letter .pv_box .pv span {
   height: 3px;
   top: 0px;
 }
+@keyframes bar-anim {
+  from { background-position: 0 0; }
+  to { background-position: 100000px 0; }
+}
 .ceval_box .bar span {
   display: block;
   height: 3px;
   width: 0;
   background: #759900;
-  transition: 1s;
+  transition: width 1s;
 }
 .ceval_box .bar span.threat {
   background: #dc322f;
 }
+.ceval_box.computing .bar span {
+  background-image: url(../images/bar-highlight.png);
+  animation: bar-anim 1000s linear infinite;
+}
 .ceval_box .show-threat {
   position: absolute;
   right: -41px;

ui/ceval/src/ctrl.js

@@ -186,6 +186,9 @@ module.exports = function(opts) {
     canGoDeeper: function() {
       return pnaclSupported && !isDeeper() && !infinite();
     },
+    isComputing: function() {
+      return !!started;
+    },
     destroy: pool.destroy
   };
 };

ui/ceval/src/view.js

@@ -146,7 +146,9 @@ module.exports = {
       else percent = 0;
     }
     var mandatoryCeval = ctrl.mandatoryCeval && ctrl.mandatoryCeval();
-    return m('div.ceval_box',
+    return m('div', {
+        class: 'ceval_box ' + (percent < 100 && instance.isComputing() ? 'computing' : '')
+      },
       enabled ? m('div.bar', m('span', {
         class: threatMode ? 'threat' : '',
         style: {