Login/logout while offline

[Brandhoej]

Description

Make sure that it is possible to login as a user when offline, this means storing credentials while online to make them available when trying to login while offline.

It is possible on synchronization that a transaction fails, find out how that can be handled gracefully.

it is possible, in an example where an user is offlline and creates an activity , and afterwards alters the activity. The user then gains connectivity and synchronization begins, it is then possible for the http request for the activity creation to fail, should we then send the alter request?