Rework debian/, following current best practices * Switch to minimal debhelper approach, Build-Depend on debhelper >= 10 * Switch from Priority 'extra' to 'optional' (deprecated as of Debian Policy v4.0.1) * Drop unused GPL-2 section from debian/copyright * Update copyright year information in debian/copyright * Refresh lintian overrides * Add postinst/postrm maintainer scripts for dpkg-maintscript-helper support