External webapp

Hey Aldo,

three suggested changes to the webapp architecture:

1. Remove distinct `app_ip` setting. Is there a special use case for this I am missing? Specifying an ip as domain/host should do the job for these cases, shouldn't it? I added an explanatory comment to the host command line flag.
2. Add an option to expose the web app externally (outside of the proxy). The implementation just spawns a second thread and heavily employs the Ostrich algorithm. Any smarter ideas? Is there an easy way open a second socket and bend the requests over to the Masterqueue? I'm not happy with the implementation, but I'd love to have that included.