Update example to use state serialization
Update example to use state serialization

The example stores the state of the API after the first
connection. During the next connection, it first tries
to restore the state from a file and only asks for the
credentials if it fails.

ocilo/skype-http,demurgos/skype-http,ocilo/skype-http,demurgos/skype-http,demurgos/skype-http,demurgos/skype-http,ocilo/skype-http,ocilo/skype-http