Import Debian changes 5.7+dfsg-3

sweethome3d (5.7+dfsg-3) unstable; urgency=medium

  * Declare compliance with Debian Policy 4.2.1.
  * Add import-library-with-OpenJDK10.patch and make it possible to import
    furniture libraries with OpenJDK 10 or later.
    Thanks to Jiri Slaby for the patch. (LP: #1773532)