Fix #114 Process doesn't exit if port is already in use

Hi,

the MarathonSchedulerService was not stopped, when shut down is triggered.
It was only necessary to implement the shutDown hook of guava service interface.

I enriched the start script to be able to pass parameter to the jvm.
All parameter with -Dxxx are passed to the jvm instead of the application.
The parameter --jvm-debug <port> sets up the agent on given port for remote debugging.
For me this was useful, perhaps it can be useful for others as well.

Cheers,
Matthias