Add notification to group chat rooms with ongoing conf calls

This notification disappears when in the conf call / when the call is over.
CSS stolen from the desktop notification bar.

skins/base/css/organisms/RoomView.css

@@ -218,3 +218,12 @@ limitations under the License.
     background-color: blue;
     height: 5px;
 }
+
+.mx_RoomView_ongoingConfCallNotification {
+    width: 100%;
+    text-align: center;
+    background-color: #ff0064;
+    color: #fff;
+    font-weight: bold;
+    padding: 6px;
+}

skins/base/views/organisms/RoomView.js

@@ -176,6 +176,15 @@ module.exports = React.createClass({
                 roomEdit = <Loader/>;
             }
 
+            var conferenceCallNotification = null;
+            if (this.state.displayConfCallNotification) {
+                conferenceCallNotification = (
+                    <div className="mx_RoomView_ongoingConfCallNotification">
+                        Ongoing conference call
+                    </div>
+                );
+            }
+
             var fileDropTarget = null;
             if (this.state.draggingFile) {
                 fileDropTarget = <div className="mx_RoomView_fileDropTarget">
@@ -192,6 +201,7 @@ module.exports = React.createClass({
                         onSettingsClick={this.onSettingsClick} onSaveClick={this.onSaveClick} onCancelClick={this.onCancelClick} />
                     <div className="mx_RoomView_auxPanel">
                         <CallView room={this.state.room}/>
+                        { conferenceCallNotification }
                         { roomEdit }
                     </div>
                     <div ref="messageWrapper" className="mx_RoomView_messagePanel" onScroll={ this.onMessageListScroll }>

skins/base/views/pages/MatrixChat.js

@@ -89,6 +89,7 @@ module.exports = React.createClass({
                 call_element = <CallView className="mx_MatrixChat_callView"/>
             }
 
+            // TODO: Fix duplication here and do conditionals like we do above
             if (Notifier.supportsDesktopNotifications() && !Notifier.isEnabled() && !Notifier.isToolbarHidden()) {
                 return (
                         <div className="mx_MatrixChat_wrapper">