remove '#include <iostream>' from headers and from unneeded places

It's harmful to have iostream everywhere as it injects functions in the compiled files

src/muz/rel/aig_exporter.cpp

@@ -108,13 +108,11 @@ namespace datalog {
                 rule *r = *II;
                 unsigned numqs = r->get_positive_tail_size();
                 if (numqs > 1) {
-                    std::cerr << "non-linear clauses not supported\n";
-                    exit(-1);
+                    throw default_exception("non-linear clauses not supported");
                 }
 
                 if (numqs != r->get_uninterpreted_tail_size()) {
-                    std::cerr << "negation of queries not supported\n";
-                    exit(-1);
+                    throw default_exception("negation of queries not supported");
                 }
 
                 exprs.reset();

src/muz/rel/dl_compiler.h

@@ -18,8 +18,6 @@ Revision History:
 --*/
 #pragma once
 
-#include<iostream>
-#include<list>
 #include<utility>
 
 #include "ast/ast.h"

src/muz/rel/dl_instruction.h

@@ -18,7 +18,7 @@ Revision History:
 --*/
 #pragma once
 
-#include<iostream>
+#include<ostream>
 #include<string>
 #include<utility>
 #include "ast/ast.h"

src/muz/rel/dl_sparse_table.h

@@ -19,7 +19,6 @@ Revision History:
 
 #pragma once
 
-#include<iostream>
 #include<list>
 #include<utility>
 

src/muz/rel/dl_table.h

@@ -18,7 +18,6 @@ Revision History:
 --*/
 #pragma once
 
-#include<iostream>
 #include<list>
 #include<utility>