Polysat: disjunctive lemmas (#5311)

* Add macro to disable linear solver for development

* Move new_* and add_* to header

* Add ref_vector_core::push_back(ref<T>&&)

* Attempt to simplify lifetime handling

* Make operator bool() explicit

* clause improvements

* display boolean assignment

* clause::resolve

* bug fixes

* more fixes

* final case of backtrack

src/math/polysat/boolean.h

@@ -58,6 +58,10 @@ namespace polysat {
         /// Set the given literal to true
         void assign(sat::literal lit, unsigned lvl, clause* reason, clause* lemma);
         void unassign(sat::literal lit);
+
+        std::ostream& display(std::ostream& out) const;
     };
 
+    inline std::ostream& operator<<(std::ostream& out, bool_var_manager const& m) { return m.display(out); }
+
 }