<unstable> Merge branch 'DA-165' into unstable
changed logs to investigate bug #278
fixed compile-error which occured due to improper refactoring of Challenge in iOSTestProject
created test and fixed bug for #279
added test for continue deserialized challenge attempt
fixed references
<issue-278> fix subscribtion after wathcing video
<issue-278> Merge branch 'unstable' into issue-278
<iOS-testing> Merge branch 'issue-278' into iOS-testing