Connected the signals emitted from plugins by relaying them to msyncd

The signals emitted from the plugin processes can be relayed over dbus
by connecting the signals to signals. This needs to be done both on the
skeleton and the stun side. With this patch, the synchronization with
the syncml client works. Tested with memotoo.com

Signed-off-by: Sateesh Kavuri <sateesh.kavuri@gmail.com>