* Move GTK compatibility macros into a separate header
* Fix Cairo compatibility checks
* Move Glib-namespaced definitions to GtkCompat header
* Remove unused stringify definitions since we're using fmtlib
* Automatically (re)order include directives (GTK client)
Include our headers first to ease IWYU enforcement.
* Fix includes missing from headers (GTK client)
* Fix build on Mac after includes reordering
* Use `Gio::List{Model,Store}` for torrents
Switch from `Gtk::{TreeModel,ListStore}` in preparation for cell
renderers deprecation in GTK 4.10. That will require switching to the
new view classes (`Gtk::{Column,List}View`) which only work with `Gio`
models. Implement an adapter to support GTK+ 3 where the old view class
(`Gtk::TreeView`) only works with `Gtk` models; it is effective enough
but requires a signal connection per item to notify on row changes.
Refactor filtering and sorting (which now happen over the new model) to
use compatible `Gtk::Filter` and `Gtk::Sorter` classes. Although these
classes are only present in GTK 4, the abstraction is suitable for GTK+
3 as well so make our subclasses work for both versions.
Since items (of `Torrent` class) of the new model provide only a very
limited (by design) layer of compatibility with GTK+ 3 way of doing
things, refactor selection handling to do it the new way. Move selection
helpers into `MainWindow` to abstract them away since new view classes
handle it differently.
* Improve session load performance based on profiling results
* Move CSS definitions to resources
* Add Gtk::Builder helpers
* Switch StatsDialog to Gtk::Builder
* Switch RelocateDialog to Gtk::Builder
* Switch OptionsDialog to Gtk::Builder
* Switch MakeDialog to Gtk::Builder
* Switch FilterBar to Gtk::Builder
* Switch MainWindow to Gtk::Builder
* Switch MessageLogWindow to Gtk::Builder
* Switch DetailsDialog to Gtk::Builder
* Switch PrefsDialog to Gtk::Builder
* Fixup translatable strings
Since this branch was brewing for a while, changes happened in the meantime.
* (C++) Macros should not be used to define constants
* (C++) Memory should not be managed manually
* (C++) "void*" should not be used in typedefs, member variables, function parameters or return type
* (C++) When the "Rule-of-Zero" is not applicable, the "Rule-of-Five" should be followed
* (C++) "switch" statements should have "default" clauses
* (C++) "explicit" should be used on single-parameter constructors and conversiosn operators
* (C++) Non-const global variables should not be used
