new specialized interfaces and visitors for subsumer rules that are
registered during indexing
some major re-factoring of rules:
* new rule interfaces for each type of conclusions
* the rules are no longer distinguished on composition/decomposition
instead there are chainable/linkable rules (those that attach to various
indexed elements) and "simple" (static) rules that can be executed
directly (previously those were called "decomposition" rules)
* the rules to conclusions can be applied in two ways: either apply all
"non-redundant" rules (for the current content of the context) or apply
all "redundant" rules. This can implement a variety of different
incremental stages.
* the incremental mode is currently broken (does not even compile), but
non-incremental tests should work
fixed compiling errors, but incremental tests don't work yet
new files for the previous commit
* ExtendedSaturationStateWriters now initialize Contexts uisng a new
conclusion ContextInitialization
* Fixed a bug with DisjointSubsumers: the incremental mode requires to
track by which subsumer it was produced (the existing test failed)
* Simplified SaturationState and SaturationStateWriter interfaces, and
other similar changes
* ConclusionVisitor is now generic, introduced new visitors
* TODO: need hybrid contexts to fix ContextCompletionFactory