Added --compress-type and --compress-level options

Starting from jessie, dpkg-deb now defaults to the xz compression type,
which is several times slower than gzip.  Since the resulting package
will typically be installed immediately and then thrown away, gzip is
probably the best default choice.

Still, the compression gain with xz is not negligible, hence the new
options.  (And we allow --force, in case dpkg-deb ever supports a new
compression type.)
Explicitly select the xz compression type for source and binary

(This is mostly cosmetic, to ensure that the package builds the same way
on wheezy as on later releases.)
Added .gitignore
Releasing eawpatches-package version 8