This also updates its manpage, some information were really old.

This reduces warnings from lintian when building Debian packages.

hn1 was deprecated for a while and this patch removes it altogether. The
support code in Cluster.hs is also removed.

This doc-patch adds copyright and license information to (hopefully) all
needed files.

In case we pass a fully-specified URL to hscan, currently it will use as
is and that means the directory in which we want to save the status
files changes from what we mean. This patch changes hscan to replace all
slashes in the cluster name with underscores when generating the output
filenames.

This moves some data from README to the man pages and has other general
improvements.

This patch adds a man page for hscan and updates the README and other
man pages with the latest changes.