The complete move to MIT license (#115)

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

Testing:

grep BSD, Patents, patents turned up nothing

lib/core/BlogPostLayout.js

@@ -1,10 +1,8 @@
 /**
  * Copyright (c) 2017-present, Facebook, Inc.
- * All rights reserved.
  *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree. An additional grant
- * of patent rights can be found in the PATENTS file in the same directory.
+ * 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");
@@ -18,8 +16,8 @@ class BlogPostLayout extends React.Component {
 
   renderSocialButtons() {
     const post = this.props.metadata;
-    
-    const fbLike = this.props.config.facebookAppId ? 
+
+    const fbLike = this.props.config.facebookAppId ?
     <div
       className="fb-like"
       data-layout="standard"