0030895: Coding Rules - specify std namespace explicitly for std::cout and streams

"endl" manipulator for Message_Messenger is renamed to "Message_EndLine".

The following entities from std namespace are now used
with std:: explicitly specified (from Standard_Stream.hxx):
std::istream,std::ostream,std::ofstream,std::ifstream,std::fstream,
std::filebuf,std::streambuf,std::streampos,std::ios,std::cout,std::cerr,
std::cin,std::endl,std::ends,std::flush,std::setw,std::setprecision,
std::hex,std::dec.

src/XmlLDrivers/XmlLDrivers_DocumentStorageDriver.cxx

@@ -393,7 +393,7 @@ Standard_Integer XmlLDrivers_DocumentStorageDriver::MakeDocument
     return myRelocTable.Extent();
   }
 #ifdef OCCT_DEBUG
-  cout << "First step failed" << endl;  // No MessageDriver available
+  std::cout << "First step failed" << std::endl;  // No MessageDriver available
 #endif
   return -1; // error
 }