Use ajax to add/remove books from shelves

Gracefully fall back to standard requests if JavaScript is disabled

cps/static/css/style.css

@@ -53,3 +53,8 @@ span.glyphicon.glyphicon-tags {padding-right: 5px;color: #999;vertical-align: te
 .spinner2 {margin:0 41%;}
 
 .block-label {display: block;}
+
+#remove-from-shelves .btn,
+#shelf-action-errors {
+    margin-left: 5px;
+}