* Merging upstream version 2.8.4+debian.
* Regenerating 01-use-libhunspell.patch.
* Updating 04-no-qt-translations.patch to also exclude qt_pl.qm.
* Regenerating 05-use-libsynctex.patch.
* Updating package description to include new polish translations.
* Switching to default xz compression level in rules.
* Rebuilding upstream tarball without:
  - conflicting debian directory
  - unused hunspell directory
  - unused include_win32 directory
  - unused include_win32_qt5 directory
  - unused qt translations
  - unused dictionary and thesaurus files
  - unused TexTablet directory
  - unused poppler-data directory