Don't stop when unmounting

This allows the project to continue playing/retain state while toggling language or player state.

src/containers/gui.jsx

@@ -66,9 +66,6 @@ class GUI extends React.Component {
             });
         }
     }
-    componentWillUnmount () {
-        this.props.vm.stopAll();
-    }
     render () {
         if (this.state.loadingError) {
             throw new Error(