add allowReturnOutsideFunction to util.parse and make nodes optional in util.template

lib/6to5/util.js

@@ -111,6 +111,11 @@ exports.template = function (name, nodes, keepExpression) {
   var template = exports.templates[name];
   if (!template) throw new ReferenceError("unknown template " + name);
 
+  if (nodes === true) {
+    keepExpression = true;
+    nodes = null;
+  }
+
   template = _.cloneDeep(template);
 
   var inherits = false;
@@ -192,13 +197,14 @@ exports.parse = function (opts, code, callback) {
     var tokens   = [];
 
     var ast = acorn.parse(code, {
-      preserveParens: true,
-      ecmaVersion:    Infinity,
-      strictMode:     true,
-      onComment:      comments,
-      locations:      true,
-      onToken:        tokens,
-      ranges:         true
+      allowReturnOutsideFunction: true,
+      preserveParens:             true,
+      ecmaVersion:                Infinity,
+      strictMode:                 true,
+      onComment:                  comments,
+      locations:                  true,
+      onToken:                    tokens,
+      ranges:                     true
     });
 
     estraverse.attachComments(ast, comments, tokens);