Implement transparent RoomTile for use in some places

where a transparent appearance is required (i.e. in MemberInfo
or ChatCreateOrReuseDialog)

src/components/views/dialogs/ChatCreateOrReuseDialog.js

@@ -59,6 +59,7 @@ export default class ChatCreateOrReuseDialog extends React.Component {
                 );
                 tiles.push(
                     <RoomTile key={room.roomId} room={room}
+                        transparent={true}
                         collapsed={false}
                         selected={false}
                         unread={Unread.doesRoomHaveUnreadMessages(room)}

src/components/views/rooms/MemberInfo.js

@@ -754,6 +754,7 @@ module.exports = withMatrixClient(React.createClass({
 
                     tiles.push(
                         <RoomTile key={room.roomId} room={room}
+                            transparent={true}
                             collapsed={false}
                             selected={false}
                             unread={Unread.doesRoomHaveUnreadMessages(room)}

src/components/views/rooms/RoomTile.js

@@ -41,6 +41,8 @@ module.exports = React.createClass({
         collapsed: PropTypes.bool.isRequired,
         unread: PropTypes.bool.isRequired,
         highlight: PropTypes.bool.isRequired,
+        // If true, apply mx_RoomTile_transparent class
+        transparent: PropTypes.bool,
         isInvite: PropTypes.bool.isRequired,
         incomingCall: PropTypes.object,
     },
@@ -188,6 +190,7 @@ module.exports = React.createClass({
             'mx_RoomTile_invited': (me && me.membership == 'invite'),
             'mx_RoomTile_menuDisplayed': this.state.menuDisplayed,
             'mx_RoomTile_noBadges': !badges,
+            'mx_RoomTile_transparent': this.props.transparent,
         });
 
         const avatarClasses = classNames({