refactoring: changing SaturationState into an interface, the same for
its writers. Lots of changes here and there, untested. Should be easier
now to create other implementations, e.g., for temporary saturation
states during incremental reasoning.
making SaturationStateImpl a package-protected class which should be
used directly.
A first-cut implementation of the new scheme without cleaning (but with
the new "gap filling" stage, which works in batches). Passes the low
level tests. Lots of small refactorings here and there to integrate it
smoothly. A couple of context initialization stages gone.