Make data returned in the respective Future instance more unified and helpful

[rweilbacher]

Currently it just returns arbitrary data. The connect future for example puts a string into it's future if it failed or the session present int if it succeeded. That makes it pretty hard to check for success and isn't very intuitive. Maybe also put success or failure into the future where currently "nothing" is being returned on success.

The changes made should then also be added to the documentation. under the respective synchronous / asynchronous sections.