Give user possibility to select a recovered file name

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Simplify the name creation of the recovered file for the user

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Check for null string too

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