Let the ExecutionService base class throw TimeoutException on failed execute

[dankwart-de]

LSF e.g. will just block and retry command submission, PBS does not (or at least our installation). Or it depends on the configuration and that can lead to funny behaviour. Anyways the developer should be aware of the fact and the TimeoutException might do just the right thing. Currently BE only offers the base class or interface, but this can then be used to force the exception.

[vinjana]

So three things need to be done:

1. Add throws TimeoutException to ExecutionService and let it actually throw the exception if the timeout is reached.
2. Add throws TimeoutException to BEJobManager.runJob() and its subclasses
3. Handle the TimeoutException in the Roddy client code (e.g. by dying and displaying a messege.).

[vinjana]

Related to #79.