Fix EventPluginRegistry Unit Tests in GitHub

Dumping the mock cache isn't dirying the modules in the open source version, so we have to unit test a different way. If we can fix the unit test framework, we should revert this.

Also, I added strict mode to `EventPluginRegistry.js`.

See: https://github.com/facebook/react/pull/91

src/event/EventPluginRegistry.js

@@ -1,4 +1,18 @@
 /**
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
  * @providesModule EventPluginRegistry
  * @typechecks
  */

src/event/__tests__/EventPluginRegistry-test.js

@@ -1,4 +1,18 @@
 /**
+ * Copyright 2013 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
  * @emails react-core
  */