gnome-shell-client: add async ctor

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
Merge branch 'wip/async-dbus'

* wip/async-dbus:
  gnome-shell-client: add async ctor

Conflicts:
	tests/gnome-shell-client/test-gnome-shell-client.c
gnome-shell-client: clear TODO

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
introduce G_PASTE_INIT_GETTEXT

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
simplify cleanup funcs

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
update TODO

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
gdbus-macros: move to core

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
nuke libgpaste-common

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>