Add new method --quant-cf for finding conflicts eagerly for quantified formulas....

Add new method --quant-cf for finding conflicts eagerly for quantified formulas.  This module can efficiently determine when there exists a conflict wrt quantified formulas that is implied by the current set of equalities, and reports the single lemma corresponding to the conflict. It does so before resorting to heuristic instantiation.  Clean up the rewriter, other minor cleanup.