moving remaining qsat functionality over

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

src/ast/rewriter/label_rewriter.h

@@ -0,0 +1,41 @@
+/*++
+Copyright (c) 2015 Microsoft Corporation
+
+Module Name:
+
+    label_rewriter.h
+
+Abstract:
+
+    Basic rewriting rules for labels.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2015-19-10
+
+Notes:
+
+--*/
+#ifndef LABEL_REWRITER_H_
+#define LABEL_REWRITER_H_
+
+#include"ast.h"
+#include"rewriter_types.h"
+
+
+class label_rewriter : public default_rewriter_cfg {
+    family_id m_label_fid;
+    rewriter_tpl<label_rewriter> m_rwr;
+public:    
+    label_rewriter(ast_manager & m);
+    ~label_rewriter();
+
+    br_status reduce_app(func_decl * f, unsigned num, expr * const * args, expr_ref & result, 
+                         proof_ref & result_pr);
+
+    
+    void remove_labels(expr_ref& fml, proof_ref& pr);
+    
+};
+
+#endif