Add simplification customization for SMTLIB2

Add the ability to customize incremental pre-processing simplification for the SMTLIB2 front-end. The main new capability is to use pre-processing tactics in incremental mode that were previously not available. The main new capabilities are
- solve-eqs
- reduce-args
- elim-unconstrained
There are several more. Documentation and exposed simplifiers are populated incrementally. The current set of supported simplifiers can be inspected by using z3 with the --simplifiers flag or referring to https://microsoft.github.io/z3guide/docs/strategies/simplifiers

Some pending features are:
- add the ability to update parameters to simplifiers similar to how tactics can be controlled using parameters.
- expose simplification solvers over the binary API.

src/tactic/arith/bound_simplifier_tactic.h

@@ -38,4 +38,5 @@ inline tactic* mk_bound_simplifier_tactic(ast_manager& m, params_ref const& p =
 
 /*
   ADD_TACTIC("bound-simplifier", "Simplify arithmetical expressions modulo bounds.", "mk_bound_simplifier_tactic(m, p)")
+  ADD_SIMPLIFIER("bound-simplifier", "Simplify arithmetical expressions modulo bounds.", "[](auto& m, auto& p, auto &s) -> dependent_expr_simplifier* { return alloc(bound_simplifier, m, p, s); }")
 */

src/tactic/arith/card2bv_tactic.h

@@ -69,4 +69,5 @@ inline tactic* mk_card2bv_tactic(ast_manager& m, params_ref const& p = params_re
 
 /*
   ADD_TACTIC("card2bv", "convert pseudo-boolean constraints to bit-vectors.", "mk_card2bv_tactic(m, p)")
+  ADD_SIMPLIFIER("card2bv", "convert pseudo-boolean constraints to bit-vectors.", "[](auto& m, auto& p, auto &s) -> dependent_expr_simplifier* { return alloc(card2bv, m, p, s); }")
 */

src/tactic/arith/propagate_ineqs_tactic.h

@@ -64,5 +64,6 @@ inline tactic* mk_propagate_ineqs_tactic(ast_manager& m, params_ref const& p = p
 
 /*
   ADD_TACTIC("propagate-ineqs", "propagate ineqs/bounds, remove subsumed inequalities.", "mk_propagate_ineqs_tactic(m, p)")
+  ADD_SIMPLIFIER("propagate-ineqs", "propagate ineqs/bounds, remove subsumed inequalities.", "[](auto& m, auto& p, auto &s) -> dependent_expr_simplifier* { return alloc(bound_simplifier, m, p, s); }")
 */