Added the ability to associate trace information with failing specs

This is meant to aid in debugging failures, particularly intermittent
failures, in cases where interactive debugging or console.log aren't
suitable.

src/html/_HTMLReporter.scss

@@ -388,4 +388,20 @@ body {
     background: white;
     white-space: pre;
   }
+
+  .jasmine-trace {
+    margin: 5px 0 0 0;
+    padding: 5px;
+    color: $light-text-color;
+    border: 1px solid #ddd;
+    background: white;
+
+    table {
+      border-spacing: 0;
+    }
+
+    table, th, td {
+      border: 1px solid #ddd;
+    }
+  }
 }