use local variables as arguments for daemoncontext

so we can do other nifty stuff, like re-use uid/gid,
extract a "default" file to redirect stdout/stderr,
and whatelse
redirect stderr/stdout to logfile

if possible
try putting PID-file into a writeable directory

when run as daemon (started as root), we want to drop root privileges
asap; unfortunately this also means, that we can no longer write
PID-files into /var/run.
solution: create a PID-directory /var/run/WILMA, that is writeable by the user.

implementation: check whether the PID-directory exists, and if it doesn't,
create it, owned by the user. (this should prevent a chown on /var/run)

we also try to remove the PID-directory on exit
prevent tuples; import needed packages