!2135 add tfrecord to mindrecord tool

Merge pull request !2135 from guozhijian/add_tools_tfrecord_to_mindrecord

mindspore/mindrecord/__init__.py

@@ -31,7 +31,8 @@ from .tools.cifar10_to_mr import Cifar10ToMR
 from .tools.cifar100_to_mr import Cifar100ToMR
 from .tools.imagenet_to_mr import ImageNetToMR
 from .tools.mnist_to_mr import MnistToMR
+from .tools.tfrecord_to_mr import TFRecordToMR
 
 __all__ = ['FileWriter', 'FileReader', 'MindPage',
-           'Cifar10ToMR', 'Cifar100ToMR', 'ImageNetToMR', 'MnistToMR',
+           'Cifar10ToMR', 'Cifar100ToMR', 'ImageNetToMR', 'MnistToMR', 'TFRecordToMR',
            'SUCCESS', 'FAILED']

tests/ut/data/mindrecord/testTFRecordData/README.md

@@ -0,0 +1 @@
+## tfrecord file dir