move spacer_marshal to under parsers/smt2

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/parsers/smt2/marshal.h

@@ -0,0 +1,27 @@
+/*++
+Copyright (c) 2017 Arie Gurfinkel
+Module Name:
+
+   marshal.h
+
+Abstract:
+
+   marshaling and unmarshaling of expressions
+
+   --*/
+#ifndef _SPACER_MARSHAL_H_
+#define _SPACER_MARSHAL_H_
+
+#include <string>
+#include <iostream>
+
+#include "ast/ast.h"
+
+std::ostream &marshal(std::ostream &os, expr_ref e, ast_manager &m);
+std::string marshal(expr_ref e, ast_manager &m);
+expr_ref unmarshal(std::string s, ast_manager &m);
+expr_ref unmarshal(std::istream &is, ast_manager &m);
+
+
+
+#endif