References #167, added field to ed_task.

Also removed to_user field and instane. The code still depends on that
field being present, thus a lot of errors are expected to arise.
References #167, fixed the nastiest errors.

Fixed any fatal errors that came from removing to_user field. Still has
a lot of code that depends on an obsolete logic. All the places will
have to be revisited and rewritten according to new logic.