unit tests failing

[David Nolden]

I fixed the problem. It was the clearArea(..) call in
"changedWorkingSet", which could happen as a result of "viewAdded",
which obviously cannot work.

The basic problem though is, that the clearArea is required. It is not
possible to safely restructure the AreaIndex structure in arbitrary
ways, which will always lead to crashes in future, when someone will
try to do some change that sublime cannot deal with right. What we
need is a more robust sublime library, where you can use all of the
view-structure related API (AreaIndex etc.) without causing major
breakages. Everything else is just a workaround.

Making working-sets a plugin will make the problem even worse, because
then, the unsafe management of the are-contents will have to become
public API. The right solution is the opposite: Push the working-sets
up into sublime (at least the non-UI part), so that they don't need to
_listen_ and _react_ to changes of the areas, but rather _be_ the
contents of the areas.

Greetings, David