convert reduce-args to a simplifier

- convert reduce-args to a simplifier. Currently exposed as reduce-args2 tactic until the old tactic code gets removed.
- bug fixes in model_reconstruction trail
  - allow multiple defs to be added with same pool of removed formulas
  - fix tracking of function symbols instead of expressions to filter replay
- add nla_divisions to track (cheap) divisibility lemmas.
-

src/ast/simplifiers/reduce_args_simplifier.h

@@ -0,0 +1,16 @@
+/*++
+Copyright (c) 2012 Microsoft Corporation
+
+Module Name:
+
+    reduce_args_simplifier.h
+
+Abstract:
+
+    Reduce the number of arguments in function applications.
+
+--*/
+#pragma once
+
+dependent_expr_simplifier* mk_reduce_args_simplifier(ast_manager & m, dependent_expr_state& st, params_ref const & p);
+