The complete move to MIT license (#115)

- headers in .js files
- update README and LICENSE year

Testing:

grep BSD, Patents, patents turned up nothing

examples/basics/pages/en/index.js

@@ -1,3 +1,10 @@
+/**
+ * Copyright (c) 2017-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
 const React = require("react");
 
 const CompLibrary = require("../../core/CompLibrary.js");