maintenance: string search methods

material.cpp

@@ -456,8 +456,9 @@ material_manager::create( std::string const &Filename, bool const Loadnow ) {
 
     auto filename { Filename };
 
-    if( filename.find( '|' ) != std::string::npos )
+    if( contains( filename, '|' ) ) {
         filename.erase( filename.find( '|' ) ); // po | może być nazwa kolejnej tekstury
+    }
 
     // discern references to textures generated by a script
     // TBD: support file: for file resources?