Implemented Skipobserver to fix bug with the polling of sync_with_server.
Without the SkipObserver when the sync modify some file start infinite loop of watchdog event-->send event to server --> recive new snapshot from server modified

Signed-off-by: k4rl85 <k4rl85@hotmail.com>
Improve search_md5 with python style

Signed-off-by: k4rl85 <k4rl85@hotmail.com>
Merge branch 'master' of github.com:corso-python-prato/share-system-team2