Rename a constant to meta FILE

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Make the MD5 hash more stable

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Move the PublicKeyManager to session (#21)

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Minor comment added, TODO removed

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Use helper method to create random root folder

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Write the public key to the meta data (#21)

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
Read the cached public keys (#21)

Signed-off-by: Nico Rutishauser <nr@hotmail.ch>
More tolerant when no persisitence meta file exists

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