message: use babel for synthetic default imports
diff: @@ -107,5 +107,10 @@ export function getTSConfig(globals, collectCoverage: boolean = false) {
  config.inlineSources = true;
  }
  + if (config.allowSyntheticDefaultImports) {
  + // compile ts to es2015 and transform with babel afterwards
  + config.module = 'es2015';
  + config.target = 'es2015';
  + }
  return tsc.convertCompilerOptionsFromJson(config, undefined).options;
  }
  