Wide coverage demo web app: translation quality feedback with colors

The background color of the translation changes to pale green, yellow or red
according to the quality.

Two types of quality indications are supported:

+ From the grammar: linearizations starting with "+" or "*" are assumed to
  be of high or low quality, respectively.
+ From the parse tree: if the root function is "?", then the translation is
  assumed to be of low quality.

If no quality indications are detected, medium quality is assumed.

src/www/wc.html

@@ -13,6 +13,9 @@ body:target h1, body:target div.modtime { display: none; }
 #extra { color: #666; }
 #pick>* { padding: 0 0.5ex; }
 #speak { display: none; }
+.default_quality { background-color: #ffc; }
+.high_quality { background-color: #cfc; }
+.low_quality { background-color: #fcc; }
 </style>
 </head>
 
@@ -63,7 +66,7 @@ body:target h1, body:target div.modtime { display: none; }
   </div>
 <p>
 <div class=modtime><small>
-<!-- hhmts start -->Last modified: Mon Mar 17 16:28:58 CET 2014 <!-- hhmts end -->
+<!-- hhmts start -->Last modified: Thu Mar 27 14:42:45 CET 2014 <!-- hhmts end -->
 </small></div>
 <script src="js/support.js"></script>
 <script src="js/gftranslate.js"></script>