meld: update to 3.21.0.

2020-04-19 meld 3.21.0
======================

  UI changes:

  * Move to a modern GTK headerbar-based design, including:
    * More extensive action support in the header bar
    * New comparison overview map widget that provides a clearer overview for
      multiple panes at once, and allows for more natural scrollbar
      positioning (Kai Willadsen)
    * Text, filename and version filters are now all accessible from the
      toolbar (Kai Willadsen)
    * Refreshed find bar that more closely matches other applications (Kai
      Willadsen)
    * Remove application menu in line with Initiatives#4 (Kai Willadsen)
    * New recent comparison selection widget (Kai Willadsen)
    * Change tab style to be full-width and hidden for single tab windows (Kai
      Willadsen)
  * Make file comparison change navigation more intuitive by changing how it
    decides where to scroll from (Heikki Ketoharju)
  * Completely refreshed Meld application icon (Alex Monday)
  * File comparison now has overscroll at the bottom of file comparisons,
    making it easier to see end-of-file differences and improving scroll
    syncing (Kai Willadsen)
  * Text wrapping, whitespace, line numbers and line highlight can now all be
    toggled from the file comparison status bar (Kai Willadsen)

  Features:

  * Add support for CVS in version control comparisons (gitqlt)
  * Copy selected file paths in folder comparison (WenGuoyao)
  * Improve dark theme detection so custom Meld highlighting better matches
    the user's theme (Kai Willadsen)
  * Meld's built-in GtkSourceView schemes now support syntax highlighting
    (Kai Willadsen)
  * Moving past the first or last change using our change navigation now
    alerts with the standard error bell (Kai Willadsen)
  * Support nightly Flatpak builds of Meld using GNOME's CI (Kai Willadsen)
  * Support development using GNOME Builder's workflow

  Fixes:

  * CI and build system fixes (Michael Behrisch, Frank Dana, Piotr Drąg, Vasily Galkin)
  * Fix running uninstalled from non-project-base folder (Vasily Galkin)
  * Fix file comparison closing after file save (Vasily Galkin)
  * Fix file comparison handling of certain line breaks (Kai Willadsen)
  * Fix folder comparison display of large file sizes (andre)
  * Fix folder comparisons with pre-epoch timestamps (Kai Willadsen)
  * Fix folder comparisons not handling ignore blank lines + text filters (Kai
    Willadsen)
  * Handle file deletion better on NFS mounts (Kai Willadsen)
  * Fix handling of bad filter regular expressions (Kai Willadsen)
  * Fix push action on missing changes in three way comparison (Kai Willadsen)
  * Default file chooser encoding to autodetect (Kai Willadsen)
  * Minor UI fixes:
    * Statusbar now correctly sets default encoding & file type for empty
      files (Kai Willadsen)
    * Statusbar tries to keep a constant width for the cursor label (Kai
      Willadsen)
    * Folder comparisons set sensitivity correctly for empty rows (Kai
      Willadsen)
    * Give commit dialog message area a reasonable height (Kai Willadsen)
    * Fix long file name wrapping in info bar notifications (Kai Willadsen)
    * Fix long file name ellipsization in file comparisons (Kai Willadsen)
  * Windows fixes:
    * Fix crash when started with unexpected environment (Vasily Galkin)
    * Fix dbus support for single-instance behaviour (Vasily Galkin)
    * Fix internationalisation building from source (ThunderEX)
    * Fix SVG icon display (Kai Willadsen)
    * Support logging to a file on Windows for debugging (Kai Willadsen)
    * Default file encoding to UTF-8 to avoid Windows-specific locale issues
      (Kai Willadsen)
  * Typo fixes (luzpaz)
  * Localisation fixes (Piotr Drąg)

  Internal changes:

  * Add Meson build system support; setuptools is still supported for Windows
    and Mac OS builds, but Linux distributions should switch to building with
    Meson (Bilal Elmoussaoui, Kai Willadsen)
  * Move from GtkUIManager to GAction-based actions
  * Move all UI-file-constructed widgets from custom Python wrapper classes
    to using real GtkWidget templates
  * Move UI templates, menus, custom icons and CSS to be resource-loaded
  * Move to pre-commit using flake8 and isort for CI linting
  * Move to new GtkSourceView 4 API
  * Modernised Python GObject API usage, including signal and property usage
  * Fix some deprecated GTK API usage
  * Support Python 3.8
  * Updated dependencies:
    * Python 3.6
    * GTK+ 3.20
    * GLib 2.48
    * GtkSourceView 4.0
    * pygobject 3.30
    * pycairo 1.15

  * Issues fixed: 62, 78, 119, 170, 240, 265, 265, 267, 279, 290, 313, 314,
    316, 321, 322, 337, 341, 342, 344, 344, 350, 351, 359, 419, 432, 439, 442,
    451

  Translations:

  * Alan Mortensen (da)
  * Anders Jonsson (sv)
  * Asier Sarasua Garmendia (eu)
  * Ask Hjorth Larsen (da)
  * Balázs Meskó (hu)
  * Balázs Úr (hu)
  * Daniel Mustieles (es)
  * Daniel Șerbănescu (ro)
  * Emin Tufan Çetin (tr)
  * Fran Dieguez (gl)
  * Guillaume Bernard (fr)
  * Jiri Grönroos (fi)
  * Kukuh Syafaat (id)
  * Marek Černocký (cs)
  * Matej Urbančič (sl)
  * Milo Casagrande (it)
  * Piotr Drąg (pl)
  * Rafael Fontenelle (pt_BR)
  * Ryuta Fujii (ja)
  * Sabri Ünal (tr)
  * sicklylife (ja)
  * Wolfgang Stöggl (de)
  * Yuri Chornoivan (uk)

(wiz)