Remove use of deprecated React.PropTypes

Replace all uses of React.PropTypes with PropTypes and importing PropTypes from
'prop-types'.

src/components/views/voip/CallView.js

@@ -14,6 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 import React from 'react';
+import PropTypes from 'prop-types';
 import dis from '../../../dispatcher';
 import CallHandler from '../../../CallHandler';
 import sdk from '../../../index';
@@ -26,25 +27,25 @@ module.exports = React.createClass({
     propTypes: {
         // js-sdk room object. If set, we will only show calls for the given
         // room; if not, we will show any active call.
-        room: React.PropTypes.object,
+        room: PropTypes.object,
 
         // A Conference Handler implementation
         // Must have a function signature:
         //  getConferenceCallForRoom(roomId: string): MatrixCall
-        ConferenceHandler: React.PropTypes.object,
+        ConferenceHandler: PropTypes.object,
 
         // maxHeight style attribute for the video panel
-        maxVideoHeight: React.PropTypes.number,
+        maxVideoHeight: PropTypes.number,
 
         // a callback which is called when the user clicks on the video div
-        onClick: React.PropTypes.func,
+        onClick: PropTypes.func,
 
         // a callback which is called when the content in the callview changes
         // in a way that is likely to cause a resize.
-        onResize: React.PropTypes.func,
+        onResize: PropTypes.func,
 
         // render ongoing audio call details - useful when in LeftPanel
-        showVoice: React.PropTypes.bool,
+        showVoice: PropTypes.bool,
     },
 
     getInitialState: function() {