* test

* rollback

* move some abvious import into head part

* rollback

* reduce utils_helper.py

* MOVE INTO DEVELOP

* add from paddle.nn import Layer

* codestyle

* remove no used fluid beam_search_decoder

* move Layer and related helper to paddle.nn.common

* modify Layer references from dygraph.layers.Layer to paddle.nn.common.layers

* stash changge

* remove fluid layer_object_helper, layers.py

* remove fluid layers init

* add setip

* fix unitest

* delete layers in fluid.dygraph

* merge paddle.tensor.stat,py

* fix circle import

* fix curcle import

* remove redundant in_dygraph_mode import

* revoce paddle.nn.common.* in fluid.__init__

* recovery nn.rnn

* paddle.frame use lazy import import paddle.jit to avoid circle import

* remove left dygraph.layers ref

* merge develop

* fix import error

* fix test error

* fxi merge error

* fix test fluid.Layer

* fix test error

* fix test error

* fix import error

* fix import error

* fix comments

* fix circle import

* fix rnn import error

* fix circle import

* fix the only one circle import in call_transformer.py

* move define of CONVERSION_OPTIONS from convert_call_func.py to program_translator.py

* delete the self import of program_translator.py

* fix import failed problem

* define variable in utils.py

* move is_builtin to utils.py

* move is_builtin to utils.py

* fix import errors

* fix import errors

* fix something

* Update python/paddle/jit/dy2static/call_transformer.py
Co-authored-by: NAurelius84 <zhangliujie@baidu.com>

* Update python/paddle/jit/dy2static/call_transformer.py

---------
Co-authored-by: NAurelius84 <zhangliujie@baidu.com>

* [Dy2St]Enhance @not_to_static API

* del breakpoint()

* Add ignore_module API

* fix type of parameter

* Add test case of ignore-module

* remove fluid.save_dygraph and fluid.load_dygraph use paddle.save and paddle.load instead

* move Sequential to paddle.nn

* modify convert_call_func.py Sequential reference

* remove related unitests

* remove fluid.dynamic.Sequntial

* test remove conver_call_func

* fix conflicts

* fix typro

* fix unitests

* fix sample_code

* fix unitest

* fix __init__

* 移除 declarative 接口

* 修改 CI报错，清理注释

* isort jit

* refine comment

* [API Clean]Clean __all__ to avoid exposing usless API

* fix import

* fix typo

* remove tracedLayer unittest

* [Dy2St] refactor convert_print to display Tensor in compile time

* [Fluid Clean]Migrate utils files and delete dygraph_to_static dir

* fix setup.py.in

* fix import

* fix unittest

* fix code style

* fix unittest

* [Fluid Clean]Migrate if/while/return/break transformer into paddle.jit

* migrate call_transformer

* migrate call_transformer

* update config

* re-blacken python code

* temporarily disable date and diff_py_file

* skip a format

* [CodeStyle] remove all future import

* revert test_error.py

* restore future import in example code

* update 2.0 public api in all left files

* reverse device.py all list;
fix some flake8 errors

Refine Dy2stat APIs to 2.0rc

After discussion, we accepted 3 key points from reviewers:

1. In 2.0rc we changed dygraph_to_static folder to dy2static
2. Keep the three files: convert_call_func.py, convert_operators.py, variable_trans_func.py
3. Remove convert_operators path when users import convert_xxx. 

After this PR, users can import convert_xxx APIs by:

`import paddle.jit.dy2static.convert_xxx`

The file structure will be:

```
jit
    dy2static
          convert_operators.py
          convert_func_call.py
          variable_trans_func.py
```

Detail changed API in files:

In python/paddle/jit/dygraph_to_static/convert_call_func.py:
from ...fluid.dygraph.dygraph_to_static.convert_call_func import convert_call  #DEFINE_ALIAS

In python/paddle/jit/dygraph_to_static/convert_operators.py:
from ...fluid.dygraph.dygraph_to_static.convert_operators import cast_bool_if_necessary  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_assert  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_ifelse  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_len  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_logical_and  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_logical_not  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_logical_or  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_print  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_var_dtype  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_var_shape  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.convert_operators import convert_while_loop  #DEFINE_ALIAS

In python/paddle/jit/dygraph_to_static/variable_trans_func.py:
from ...fluid.dygraph.dygraph_to_static.variable_trans_func import create_fill_constant_node  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.variable_trans_func import create_static_variable_gast_node  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.variable_trans_func import data_layer_not_check  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.variable_trans_func import to_static_variable  #DEFINE_ALIAS
from ...fluid.dygraph.dygraph_to_static.variable_trans_func import to_static_variable_gast_node  #DEFINE_ALIAS

* Move hapi form paddle/incubate to paddle

* Remove vision/datasets/utils.py and clean code

* Add sample code for conll05

* Print pull path when saving model

* Fix sample code after paramter_list of SGD is changed to parameters

* Fix bug in wmt16 datase

* Add hapi.text and corresponding unit test.
test=develop

* Remove hapi.text apis' reuse parameter args for coverage.
test=develop

* Fix TransformerCell and TransformerBeamSearchDecoder example codes.
test=develop

* Fix example codes in hapi.text.
test=develop

* Add some apis in hapi.text into example code white list.
test=develop

* Fix example code of DynamicDecode in hapi.text.
text=develop

* Rename Model.self as model in test_text.py
test=develop

* fix high level API(Inference) bug

* patch the unit tests

* Use for_test=True in the Fluid Trainer to clone the test program

* fix typo

* Should do the samething to the inferencer

* add Inference.infer

* optimize code

* update no_test_word2vec_new_api.py

* update trainer

* split check_and_get_place

* use inference_program to save inference model in Trainer

* update demo

* update save_inference_model

* clean code

* Load/save the params from the params_path

* Switch to use load_persistables and save_persistables

* Instaed of setup the executor to run program and scope. Pass the program to the load_persistables

- The trainer and inferencer will load params from disk if param_path
  argument is not None in their constructor.

- Remove params.py, we will expose core.Scope to the user if needed
  (e.g., for GAN). Currently we will not expose it, unless we clearly
  know doing so can support GAN.

- Add `save_params` to Trainer (a TODO item).

- rename "network" to "program"