uscan debian/watch signature support

Key downloaded from http://savannah.nongnu.org/users/winkler which
points to http://savannah.nongnu.org/people/viewgpg.php?user_id=46353
resulting in an ascii-armored DOS-format file named winkler-key.gpg
which was processed by dos2unix and moved to upstream/signing-key.asc
Merge branch 'debian-v3.x' into debian-uuid