FIXED : After an operation started, either from a queue or explicitely, its finished property was never set to true.
This was causing dependant operation to never be executed.
After this commit, cancelled operations are started (but not executed) and correctly marked as finished.
Tests: CPOperationQueueTest and CPOperationTest for an operation managed by a queue or run explicitely.
All classes (excluding the ones prefixed with underscores) in Foundation
and AppKit can now be loaded individually except CPOpenPanel and
CPSavePanel. These two classes have some sort of dependency cycle
that seems impossible to resolve without forward declarations (which
we don't have).