Merge branch 'master' of https://github.com/PaddlePaddle/X2Paddle

TensorFlow2Paddle/README.md

-### Warning: TensorFlow2Paddle is not stable yet. Only tested on vgg_16/resnet_v1_50/inception_v3 with is_training=False
+### Warning
+> **TensorFlow2Paddle is not stable and lots of tensorflow operations are not supported yet**
 
-#### Demo: How to change tensorflow resnet_v1_50 pretrained model to PaddlePaddle model for inference
-##### 1. Get pretrained_model
+> **Only tested on vgg_16/resnet_v1_50/inception_v3 with is_training=False**
+
+### Dependency
+> 1. python = 2.7
+> 2. PaddlePaddle >= 1.2.0
+> 3. TensorFlow >= 1.12.0
+
+**Notice：You can install PaddlePaddle and Tensorflow in different virtual environment since there's dependency conflict between PaddlePaddle and TensorFlow**
+
+### Demo: How to change tensorflow resnet_v1_50 pretrained model to PaddlePaddle model for inference
+#### 1. Get pretrained_model
 
 ```
 git clone https://github.com/PaddlePaddle/X2Paddle.git
@@ -10,20 +20,20 @@ wget http://download.tensorflow.org/models/resnet_v1_50_2016_08_28.tar.gz
 tar xzvf resnet_v2_50_2017_04_14.tar.gz
 ```
 
-##### 2. Change model to ckpt model with meta file
+#### 2. Change model to ckpt model with meta file
 
 
 ```
 python demo/save_resnet_ckpt_model.py resnet_v1_50.ckpt ./new_ckpt_model
 ```
 
-##### 3. Export PaddlePaddle model
+#### 3. Export PaddlePaddle model
 
 ```
 python demo/export_resnet_to_paddle_model.py new_ckpt_model/resnet.meta new_ckpt_model fluid_model
 ```
 
-##### 4. Test PaddlePaddle model
+#### 4. Test PaddlePaddle model
 ```python 
 from fluid_model.mymodel import KitModel
 import paddle.fluid as fluid