bluegriffon: import 1.7.2-1~getdeb1

Obtained from http://ftp.dk.debian.org/getdeb/ubuntu/pool/apps/b/bluegriffon/
bluegriffon: update debian/watch to point to our upstream

Getdeb seems to do everything very well, let's consider them as our
upstream since they provide clean upstream sources for our purposes.
bluegriffon: add get-orig-source target