<NME> mocha-support.js
<BEF> ADDFILE
<MSG> allow .skip and .only on top level modules.

This allows you to mark top-level describeModule and friends as
pending. It also allows you to set them as the only scope to run.

This brings the api in line with vanilla mocha `describe`

<DFF> @@ -0,0 +1,20 @@
+/**
+ * Captures mocha grep options for a. That way you can run describe
+ * block or an `it` block that may narrow the mocha test run, but
+ * those options will be reset afterwards. E.g.
+ *
+ *   var grep = grepFor(function() {
+ *     it.skip('this is skipped');
+ *   })
+ *   console.log(grep) //=> /this is skipped/
+*/
+export function grepFor(fn) {
+  var options = window.mocha.options;
+  var originalMochaGrep = options.grep;
+  try {
+    fn();
+    return options.grep;
+  } finally {
+    options.grep = originalMochaGrep;
+  }
+}

allow .skip and .only on top level modules.