Do not close/unlock study until it is completely stopped

[odeimaiz]

When a user closes a study a tear down process starts.

At the moment, as soon as a user calls study:close and the entry is removed from the active studies database, the study is available again to be opened. Nevertheless, the services in that study need to be properly closed (save state and close).

I propose that the study remains closed/locked until all parts are closed.