incorporate a fix from smtcomp2010 version for handling CNF of (= bool bool); also...

incorporate a fix from smtcomp2010 version for handling CNF of (= bool bool); also make theoryOf(= t1 t2) return theoryOf(t1.getType()), rather than theoryOf(t1), as the latter gives different results for (= (geq x1 x2) (leq x2 x1)) and (= a (leq x2 x1)), which is strange and causes problems.  should discuss at tuesday meeting.  resolves bug 187.