Log Message:
meta-pkgs/xfce4: update to 4.16

Project summary of changes:

Today, after 1 year and 4 months of work, we are happy to announce the release \ 
of the Xfce desktop 4.16, a new stable version that supersedes Xfce 4.14.

4.16 was a special cycle in many respects (not only pandemic-wise, but also). \ 
One of the corner-stones of the non-code changes concerns our migration to \ 
GitLab, which is a change in development workflow and a huge step forward in \ 
terms of becoming more contributor-friendly and welcoming. In parts, the \ 
humungous changelog of Xfce 4.16 can be attributed to new contributors proposing \ 
merge requests (288 merge requests were merged or closed against our core \ 
components alone!). We also created a reference Docker container \ 
(xfce/xfce-build) and added CI pipelines to all components to ensure we don´t \ 
break the build. None of this would have been possible without our hosting being \ 
sponsored by Gandi and Fosshost!

Another big change concerns our visual identity, which we updated from a strange \ 
mix of random (partly Tango-based) icons and not following any naming scheme to \ 
a new, visually consistent set (following the freedesktop.org naming \ 
specification and a fixed color palette). We´re aware this will generate some \ 
work for icon theme maintainers (if they really want to override our gorgeous \ 
icons ;)) but we believe the longterm benefit outweighs this one-time effort.

And then finally we did some housekeeping (e.g. by dropping Gtk2 support code) \ 
and we also added features and improvements - all while sticking to a reasonable \ 
release cycle timeframe.

So without further ado, here go the main highlights of this release:

    The window manager received lots of updates and improvements again in the \ 
area of compositing and GLX. If a primary display was set, the alt-tab dialog \ 
will now only be shown there. Furthermore some handy new options to zoom the \ 
cursor along with rest of the display as well as an option to keep minimized \ 
windows in the most recently used list complement this release.
    We added a new plugin to the panel dubbed "statustray" which \ 
combines both StatusNotifier and legacy Systray items. An animated autohide \ 
transition now clearly shows the user "where the panel has gone" and a \ 
dark mode (enabled by default) makes the panel drop into the background a bit \ 
more with bright themes like the Gtk default Adwaita. Quite a few more smaller \ 
improvements were also introduced like accessing desktop actions from a \ 
Launcher´s right-click menu, the Window Buttons plugin now offering to `Launch \ 
a new instance` of an application and the Workspace Switcher now optionally \ 
showing automatic numbering for workspaces.
    Support for fractional scaling was added to the display dialog, along with \ 
highlighting the preferred mode of a display with an asterisk and adding aspect \ 
ratios next to resolutions. Falling back to a working mode after misconfiguring \ 
the display layout has also been made more robust.
    A new tab in the "About Xfce" dialog shows basic system \ 
information like CPU or GPU type. Furthermore the layout and visuals of the \ 
dialog were improved.
    The settings manager has improved search and filter capabilities. \ 
Furthermore all settings dialogs now use window decorations drawn by Gtk (client \ 
side decorations).
    The "Mime Settings" and "Preferred Applications" dialogs \ 
were merged into the "Default Applications" dialog - making it easier \ 
for users to set which application handles which filetype or action from one \ 
place.
    Our file manager Thunar received a boatload of fixes and quite a few notable \ 
features, including pause for copy/move operations, support for queued file \ 
transfer, remembering view settings per directory and support for transparency \ 
in Gtk themes.
    Our thumbnailing service tumbler became more flexible by being able to \ 
exclude paths. Furthermore support for .epub (e-book format) was added.
    The session manager offers improved support for GPG agent 2.1 and the \ 
setting dialog was visually improved.
    The power manager received a lot of bugfixes and some smaller features - \ 
among them a cleanup of its settings dialog, an optional visual indicator for \ 
when `Presentation Mode` is enabled, more accurate battery status icons and \ 
automatically dismissing low-power notifications upon the connection of a \ 
charger.
    The desktop mostly received bugfixes and small improvements - and the new \ 
default wallpaper!
    Our menu library garcon received new APIs and now doesn´t launch \ 
applications as children of the process hosting the menu anymore. The previous \ 
behavior led to applications crashing along with e.g. the panel.
    The applicaton finder now allows for sorting applications by \ 
"frecency" - a combination of frequency and recency.
    Dependency updates: Drop Gtk2, add LibGTop, bump Gtk >= 3.22, GLib and \ 
GDBus >= 2.50