Refactor iuc_proof as a separate class

This also adds DOT printing support to interpolating proofs
(color for different parts)

iuc_proof is a proof used for IUC computation

src/muz/spacer/spacer_iuc_proof.h

@@ -0,0 +1,65 @@
+#ifndef IUC_PROOF_H_
+#define IUC_PROOF_H_
+
+#include "ast/ast.h"
+
+namespace spacer {
+    typedef obj_hashtable<expr> expr_set;
+    typedef obj_hashtable<func_decl> func_decl_set;
+
+    /*
+     * an iuc_proof is a proof together with information of the coloring of the axioms.
+     */
+    class iuc_proof
+    {
+    public:
+        
+        iuc_proof(ast_manager& m, proof* pr, expr_set& b_conjuncts);
+        
+        proof* get();
+
+        /*
+         * returns whether symbol contains only symbols which occur in B.
+         */
+        bool only_contains_symbols_b(expr* expr) const;
+
+        bool is_a_marked(proof* p);
+        bool is_b_marked(proof* p);
+        bool is_h_marked(proof* p);
+
+        bool is_b_pure (proof *p)
+        {return !is_h_marked (p) && only_contains_symbols_b (m.get_fact (p));}
+
+        /*
+         * print dot-representation to file proof.dot
+         * use Graphviz's dot with option -Tpdf to convert dot-representation into pdf
+         */
+        void pp_dot();
+        
+        void print_farkas_stats();
+    private:
+        ast_manager& m;
+        proof_ref m_pr;
+        
+        ast_mark m_a_mark;
+        ast_mark m_b_mark;
+        ast_mark m_h_mark;
+        
+        func_decl_set m_symbols_b; // symbols, which occur in any b-asserted formula
+
+        // collect symbols occuring in B
+        void collect_symbols_b(expr_set& b_conjuncts);
+
+        // compute for each formula of the proof whether it derives from A and whether it derives from B
+        void compute_marks(expr_set& b_conjuncts);
+        
+        void pp_dot_to_stream(std::ofstream& dotstream);
+        std::string escape_dot(const std::string &s);
+        
+        void post_process_dot(std::string dot_filepath, std::ofstream& dotstream);
+    };
+    
+    
+}
+
+#endif /* IUC_PROOF_H_ */