onTileUpdate -> onMessageAllowed

We keep onTileUpdate in MessgeEvent because it's a generic thing for the class to handle. onMessageAllowed is slightly different than onShowAllowed because "show allowed" doesn't quite make sense on its own, imo.

src/components/views/messages/MessageEvent.js

@@ -112,7 +112,7 @@ module.exports = createReactClass({
             replacingEventId={this.props.replacingEventId}
             editState={this.props.editState}
             onHeightChanged={this.props.onHeightChanged}
-            onTileUpdate={this.onTileUpdate}
+            onMessageAllowed={this.onTileUpdate}
         />;
     },
 });