Processing in separate threat may cause racing condition and timeouts in browser.
By putting processing in original threat we get a more sequential processing and more stability.
In WPF application the HttpProcessor was newer released and got stuck in method "StreamReadLine".
This causes the application to stay alive with a zombie-process...
By introducing IDisposable-interface containing an "active" flag we can shut the processor down.
putting the processor in "using" it will be disposed once HttpServer is shut down.
sealed StringAttribute because it is only contains text as attribute
sealed SpotifyWebAPI class as it implements IDisposable
Changed Exception catching where the Exception is not used to ignore the Exception object
Removed Console.WriteLine("Exception: " + e.Message) int HttpProcessor.Process as it is a library function which might not be used in a console application
