Allow Reasoner nodes to be Or-nodes
If a logic generates rules for a set of formulas, then these are treaten conjunktively. I.e. The set of formulas is satisfiable iff all of the successors are satisfiable. For our direct implementation of GML, we need disjunctive behaviour: the set of formulas is satisfiable as soon one possible rule application is decidable.
So functors should be able to decide wether the set of produced rules is an And- or an Or-node.