gpaste-client: track connection errors

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

Conflicts:
	src/gpaste/gpaste.c
fix README

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
clipboards-manager: use Xfixes

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

Conflicts:
	libgpaste/core/gpaste-clipboards-manager.c
update TODO

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