Receive multiple messages per frame and fix some unhandled exceptions

Some last edits, which I did to improve the performance, so I could display my thesis presentation using the WebView in UFrameIT. There will probably be some small merge conflicts with your changes @baletiballo , but nothing too complicated. Unfortunately I will not have the time to merge and test this.

Runs AsyncReadLoop in a c# background thread (using Task.run) to be able to receive more then one message per Unity update() call.