HOSTNAME variable on RunCtrl PC needed for distributed operation

[dreyling]

If the the HOSTNAME variable is not set as the (local) IP, then the RunControl can send something to the connected components, but the communication back is not working. This is probably related to this query

main/lib/src/TransportTCP.cc:    const char *host = getenv("HOSTNAME");

The start scripts should be improved or this should be removed in order to avoid start-up problems.