Use prop-types package instead React.PropTypes for typechecking

Using React.PropTypes is deprecated since React v15.5
Details: https://facebook.github.io/react/blog/2017/04/07/react-v15.5.0.html#migrating-from-react.proptypes

Author: v12

package.json

@@ -90,5 +90,8 @@
   },
   "release-script": {
     "bowerRepo": "git@github.com:react-bootstrap/react-router-bootstrap-bower.git"
+  },
+  "dependencies": {
+    "prop-types": "^15.5.8"
   }
 }

src/LinkContainer.js

@@ -1,4 +1,5 @@
-import React, { Component, PropTypes } from 'react';
+import React, { Component } from 'react';
+import PropTypes from 'prop-types';
 import { Route } from 'react-router-dom';
 
 const isModifiedEvent = (event) =>