tomb doesn't need lsof for anything else, and can work regulary without it.
So make it an optional feature, which allows to slam a tomb if lsof is installed
Updates additionally the man page and generates a new pdf from it
Apparantly fuser didn't report back, if the tomb was mounted in a subdir of /run (whereas /run itself is often a tmpfs mount).
With no list of process ids those couldn't be killed, so slamming the tomb failed.
lsof is capable to report back the sought information.
Fixes#220
Additionally fixing the debug output, where a hardcoded mountpoint was used
The fix is due to the new naming scheme without .tomb extension recently
introduced for mountpoints. While testing this a problem arised with
swish-e related to compression of indexes, to be addressed.
