Fix conversion file parsing error handling in `Editor::convert_tiles_…

…by_file`

src/editor/editor.cpp

@@ -727,27 +727,22 @@ Editor::convert_tiles_by_file(const std::string& file)
   {
     IFileStream in(file);
     if (!in.good())
-    {
-      log_warning << "Couldn't open conversion file '" << file << "'." << std::endl;
-      return;
-    }
+      throw std::runtime_error("Error opening file stream!");
 
     int a, b;
     std::string delimiter;
     while (in >> a >> delimiter >> b)
     {
       if (delimiter != "->")
-      {
-        log_warning << "Couldn't parse conversion file '" << file << "'." << std::endl;
-        return;
-      }
+        throw std::runtime_error("Expected '->' delimiter!");
 
       tiles[a] = b;
     }
   }
   catch (std::exception& err)
   {
     log_warning << "Couldn't parse conversion file '" << file << "': " << err.what() << std::endl;
+    return;
   }
 
   for (const auto& sector : m_level->get_sectors())