message: Print error messages from model loaders
diff: #include <common/config.h>
  +#include <iostream>
  +#include <ostream>
  #include <type_traits>
  #include <unordered_map>
  @@ -186,6 +188,11 @@ bool model::load(std::vector<std::string> const& filenames)
  return success;
  }
  }
  + catch (std::exception& e)
  + {
  + std::cerr << e.what() << '\n';
  + return false;
  + }
  catch (...)
  {
  return false;
  