Update copyright headers (reactjs#3086)

Added and updated copyright headers.

Added some missing Flow types.

Removed an invalid prop-types import.

Author: Brian Vaughn

flow-typed/gatsby.js

@@ -1,3 +1,7 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ */
+
 declare module 'gatsby' {
   declare module.exports: any;
 }

flow-typed/glamor.js

@@ -1,3 +1,7 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ */
+
 declare module 'glamor' {
   declare module.exports: {
     css: {

flow-typed/hex2rgba.js

@@ -1,3 +1,7 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ */
+
 declare module 'hex2rgba' {
   declare module.exports: (hex: string, alpha?: number) => string;
 }

flow-typed/react-helmet.js

@@ -1,3 +1,7 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ */
+
 declare module 'react-helmet' {
   declare module.exports: any;
 }

flow-typed/slugify.js

@@ -1,3 +1,7 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ */
+
 declare module 'slugify' {
   declare module.exports: any;
 }

gatsby-browser.js

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2013-present, Facebook, Inc.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * @emails react-core
  */

gatsby-config.js

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2013-present, Facebook, Inc.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * @emails react-core
  */

gatsby-node.js

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2013-present, Facebook, Inc.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * @emails react-core
  */

gatsby/createPages.js

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2013-present, Facebook, Inc.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * @emails react-core
  */

gatsby/onCreateNode.js

@@ -1,5 +1,5 @@
 /**
- * Copyright (c) 2013-present, Facebook, Inc.
+ * Copyright (c) Facebook, Inc. and its affiliates.
  *
  * @emails react-core
  */