Now that D-Bus has been fully reimplemented with txdbus, GLib is not needed anymore for
D-Bus bridge.
As `dbus` and `pb` (and future other bridges) both support "AIOBridge", we don't have to
use a Twisted specific version for anything.
The loop was chosen according to the bridge used, but this is not possible anymore before
running it, because there is now an "auto" bridge which falls back from D-Bus to PB. To
work around that, the loop has been refactored to be started before knowing which bridge
is used, then the bridge-dependent hooks are installed later.
``call`` commands now handle various output. Beside the original one (now named
``simple``), a new ``gui`` one display a full featured GUI (make with Qt).
PyQt 6 or more needs to be installed.
rel 427
