feat: typed client /(un)assignroles - fixes #632

 - implement IReturn on AssignRoles / UnAssignRoles
Merge pull request #635 from Iristyle/assignroles-typed-client

feat: typed client /(un)assignroles - fixes #632
Changing back CultureNotFoundException does not exist in .NET 3.5. #634
Merge remote-tracking branch 'upstream/master'