bugid:419

Start RSPDriver, CalServer and BeamServer in background (detached from
terminal) when they are passed a "-d" option ('d' for daemon).

All file-descriptors are closed to LofarLogger must be set up correctly
with .log_prop files to output logging to a file.

rspdriver.in, calserver.in and beamserver.in init scripts now use
'daemon' function to start the server in the background.