Show end call button in states other than connected and ringback: it's perfectly valid to want to end the call at other times.

Fixes #9

src/skins/vector/views/molecules/RoomHeader.js

@@ -53,17 +53,12 @@ module.exports = React.createClass({
             var topic = this.props.room.currentState.getStateEvents('m.room.topic', '');
 
             var callButtons;
-            if (this.state) {
+            if (this.state && this.state.call_state != 'ended') {
-                switch (this.state.call_state) {
-                    case "ringback":
-                    case "connected":
                 callButtons = (
                     <div className="mx_RoomHeader_textButton" onClick={this.onHangupClick}>
                         End call
                     </div>
                 );
-                        break;
-                }
             }
 
             var name = null;