Update GCDWebServer.m

```
dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void){
        //Background Thread
        [webServer runWithPort:8080 bonjourName:httpServiceName];
        
        dispatch_async(dispatch_get_main_queue(), ^(void){
            //Run UI Updates
        });
    });
```