Revert "fix ipol"

This reverts commit 20751b56.

Code/Seg/IPOLdemo/mainIPOL.cpp

@@ -32,7 +32,7 @@ int main (int argc, char *argv[])
   // - output file
   string output_filename = argv[2];
   ofstream fout;  
-  fout.open(output_filename.c_str(), std::fstream::out);
+  fout.open(output_filename, std::fstream::out);
 
   
 // Calcul de la carte de gradient (utilise qt)