update word2vec to work with current train api

demo/word2vec/train_v2.py

@@ -58,7 +58,8 @@ def main():
         if isinstance(event, paddle.event.EndIteration):
             if event.batch_id % 100 == 0:
                 result = trainer.test(
-                    paddle.dataset.imikolov.test(word_dict, N), 128)
+                    paddle.batch(
+                        paddle.dataset.imikolov.test(word_dict, N), 32))
                 print "Pass %d, Batch %d, Cost %f, %s, Testing metrics %s" % (
                     event.pass_id, event.batch_id, event.cost, event.metrics,
                     result.metrics)
@@ -70,10 +71,9 @@ def main():
         regularization=paddle.optimizer.L2Regularization(8e-4))
     trainer = paddle.trainer.SGD(cost, parameters, adam_optimizer)
     trainer.train(
-        paddle.dataset.imikolov.train(word_dict, N),
+        paddle.batch(paddle.dataset.imikolov.train(word_dict, N), 32),
         num_passes=30,
-        batch_size=128,
-        event_handler=event_handler, )
+        event_handler=event_handler)
 
 
 if __name__ == '__main__':