increase timeout for require js modules for initial loads (#1596)

lib/src/barback/dartdevc/dartdevc.dart

@@ -100,6 +100,7 @@ Map<AssetId, Future<Asset>> bootstrapDartDevcEntrypoint(
 
     var bootstrapContent = '''
 require.config({
+    waitSeconds: 30,
     paths: {
       ${customModulePaths.join(',\n      ')}
     }