* replace paddle.fluid.layers.data and remove io.data

* partial commit

* partial commit

* partial commit

* partial commit

* partial commit

* partial commit

* remove data in fluid.layers.io.__all__

* fix errors

* fix unitests

* fix unitest

* fix unitests

* fix unitest

* fix unitest

* fix unitests

* fix unitest

* fix test_layers unitests

* fix typro

* fix unitest

* fix unitest

* fix unitest

* fix typro

* fix unitest test_model_cast_to_bf16

* fix test_reducescatter

* fix collective unitest

* fix collective unitests

* fix collective unitests

* add coverage

* fix add layers.data

* re run ci

* fix some typro

* fix samplecode error

* fix samplecode error

* move fc from fluid to paddle2.0

* fix unit test

* fix some examples

* fix some examples

* remove lstm api

* remove gru_unit api

* remove lstm in all

* remove beam-search

* remove beam_search slot

* remove lstm test code

* remove fluid.layers.nn api

* update gru-unit

* revert gru_unit white list

* replace layers.cross_entropy with paddle.entropy

* fix args

* fix codestyle

* mv accuracy and auc

* rm distributions

* rm get_places

* replace metric

* remove lod_tensor_to_array, array_to_lod_tensor, DynamicRNN

* remove less_equal, greater_than, greater_equal, equal, not_equal

* add isort config

* isort all files

* remove apis in fluid.ops

* fix test_activation_nn_grad

* fix circle import error

* fix ops

* fix cos

* fix divide not inplace

* remove lazy-import part

* 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

* change fluid.mean to paddle.mean

* reverse some old code examples

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

test=develop

In this way we can build and test using WITH_FLUID_ONLY flag being set
to ON.

- move paddle.v2.dataset,reader to paddle.dataset,reader
- remove unused code (which depends on v2) in paddle.dataset,reader

* merge fluid dist tests

* update cmake

* Generated functions can take `*args` as inputs.

* Support parallel test for understand_sentiment

* Full test on understand_sentiment

* Skip normal tests

* Debug CI

* Enable benchmark

* Revert init.cc

* Make CI pass

Use a new scope for inference in python unittest to avoid changing the value of variables for training.

* initial commit

* fix bug

* end of file fix

* address comments

Into one unit test file