refine README.md for v1_api_demo and v1_api_tutorials

doc/v1_api_tutorials/README.md

-The tutorials in v1_api_tutorials are using v1_api now, and will be upgraded into v2_api later.
+The tutorials in v1_api_tutorials are using v1_api currently, and will be upgraded to v2_api later.
 Thus, v1_api_tutorials is a temporary directory. We decide not to maintain it and will delete it in future.
 
 Please go to [PaddlePaddle/book](https://github.com/PaddlePaddle/book) and 

v1_api_demo/README.md

-The examples in v1_api_demo are using v1_api now, and will be upgraded into v2_api later.
+The examples in v1_api_demo are using v1_api currently, and will be upgraded to v2_api later.
 Thus, v1_api_demo is a temporary directory. We decide not to maintain it and will delete it in future.
 
 Please go to [PaddlePaddle/book](https://github.com/PaddlePaddle/book) and