Condition module.exports to make commonjs version work in browsers and not throw an error.

mustache-commonjs/mustache.js.tpl.post

@@ -1,7 +1,8 @@
+if (typeof module !== 'undefined' && module.exports) {
+    exports.name = Mustache.name;
+    exports.version = Mustache.version;
 
-exports.name = Mustache.name;
-exports.version = Mustache.version;
-
-exports.to_html = function() {
-  return Mustache.to_html.apply(this, arguments);
-};
+    exports.to_html = function() {
+      return Mustache.to_html.apply(this, arguments);
+    };
+}