* New upstream release
* debian/patches/20_doc_install_path, debian/rules
  - install the documentation in the expected Debian directory, so part of doc
    installation was semplified in rules
* debian/{control, rules}
  - added python-pygraphviz-dbg package
* debian/copyright
  - extended packaging copyright years
  - updated upstream copyright years
* debian/control
  - bump Standards-Version to 3.9.2 (no changes needed)