message: Fix GroupMemberList search for users without displayname
  When there is a user in a group which has no displayname set
  the search failed with "Cannot read property 'toLowerCase' of null"
diff: @@ -92,7 +92,7 @@ export default withMatrixClient(React.createClass({
  query = (query || "").toLowerCase();
  if (query) {
  memberList = memberList.filter((m) => {
  - const matchesName = m.displayname.toLowerCase().indexOf(query) !== -1;
  + const matchesName = (m.displayname || "").toLowerCase().includes(query);
  const matchesId = m.userId.toLowerCase().includes(query);
  if (!matchesName && !matchesId) {
  