Fixing some issues during sharing

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Add verification before adding a file (+ tests)

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Notifying own clients when someone shared with me

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Move: the users are now notified correctly

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Fixing TTL and sharing a non-empty folder

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Two steps for ttl and basedOn (easier to uncomment)
+ old code deletion

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>