message: Use an arrow function to allow `this`
  This was causing `TypeError: Cannot read property '_getEmptyContent' of undefined` for those with custom tags.
diff: @@ -578,7 +578,7 @@ module.exports = React.createClass({
  onHeaderClick={ self.onSubListHeaderClick }
  onShowMoreRooms={ self.onShowMoreRooms } />
  - { Object.keys(self.state.lists).map(function(tagName) {
  + { Object.keys(self.state.lists).map((tagName) => {
  if (!tagName.match(/^(m\.(favourite|lowpriority)|im\.vector\.fake\.(invite|recent|direct|archived))$/)) {
  return <RoomSubList list={ self.state.lists[tagName] }
  key={ tagName }
  