* cache core.ops, test=develop

* refine, test=develop

* softmax mask fuse upper triangle

* cover not implemented cpu code

* update 2.0 public api in all left files

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

* remove fluid for auto_checkpoint.

* fix bug.

* Remove old custom OP to reduce whl package volume

* [Custom OP]Remove old custom OP to reduce whl package volume

* test=develop, fix test_lookahead

* test=develop, add model_average and lookahead

* add + - * / @ [] operator to ComplexVariable, also add unittest

* fix circular reference bug

* fit for py2.7

* remove reverse oprators which not supported now

* refine parameters order && doc

* update rmsprop doc

* refine adam/transpose/unstack/stride_slice

* fix bug && doc

* fix doc

* bug fix

* bug fix

* fix doc

* fix doc

* fix doc

* fix doc

* depercate old strided_slice

* update doc

* set default value for name

* update doc

* 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

* fix bug

* fix sample code for hapi.model.save, test=document_fix

* test=document_fix

* update usage of 2.0 API, test=document_fix

* fix bugs, return dygraph back to users while using model.save in dygraph

* fix code style

* refine manual seed

* fix ci problem

* fix unittests

* fix unittest

* set is_init_py=false in manual_seed

* fix unittest

* fix bernoulli_op

* fix(unittest): change random_seed to manual_seed

* 🐞fix(unittest): fix manual_seed

* trigger ci

* fix test_sentiment

* fix test_imperative_save_load

* fix test_uniform_random_op

* fix test_uniform_random_op

* fix test_jit_save_load

* merge develop

* fix manual_seed

* fix manual_seed

* use global engine

* use shared_ptr

* fix double free

* fix bug

* fix bug

* fix bug

* fix test bug

* fix test bug

* fix test bug

* fix ci

* add InputSpec

* add unittest for tensorSpec and SimpleNet

* update save_inference_model for hapi

* update save_inference_model to support dygraph

* fix comments

* fix comments

* test=develop

* test, test=develop

* fix dim test, test=develop

* test, test=develop

* add test_export_deploy_model_dynamic

* fix unittest for hapi: save_inference_model

* fix code style

* accept review by guoshengCS

* fix coverage rate

* update doc for save_inference_model and copyright

* change test model back to LeNet() in test_export_deploy_model

* copy jit.save, use LeNet() to test export deploy model

* add return value for dygraph, and fix doc error

* corrected the doc writing

* Delete redundant import and correct import order in sample code.

* remove 'fluid' and add prepare() and fit() in sample code

* correct usage of API 2.0 in sample code

* fix sample code bugs

* fix code style bugs

* fix test_model.py bugs

* set for_inference=True

* correct usage for static.InputSpec

* update doc for model.save

* correct usage of API 2.0

* rename param name for model.save

* correct for_inference as training

* Move paddle/incubate/hapi/metrics to paddle/metric
* Add Precision, Recall and Auc metric

* fix resource warning. test=develop

* update Conv2d Conv3d conv2d conv3d api

* add map_style dataset. test=develop

* Rename `Input` into `InputSpec`

* fix argument place of Input api

* 1.Fix api sum:(1) input->sum; (2)dim->axis; (3)keep_dim->keepdim.

* 2. fix bug when len(axis) == len(x.shape). 

* expose and unify the Tensor concepts to the user

* expose tensor to user

* add copy place for Tensor

* add copy place for Tensor

* add note

* add macro PADDLE_WITH_CUDA

* remove RUN_TYPE=DIST

* fix some error

* Directory migration, test=develop

* Change imperative from paddle init to paddle framework, test=develop

* Fixed jit bug, test=develop

* default static mode, test=develop

* fixed format and create parameter belongs to framework, test=develop

* Fixed import package, test=develop

* fix __init__ format, test=develop

* fixed alias problem

* fixed paddle.enable_imperative problems, test=develop

* Add unittest

* delete install_check comment

* Fixed unittest timeout

* fixed unittest error

* move Program default_xx_program to static package

* optimize unittest method

* fixed framework __init__ format

* fixed jit path

* delete alias

* move jit to paddle

* Fixed unittest format

* fixed paddle.default_main_program

* Fixed save load API in paddle __init__.py

* fixed ci paddle.imperative.to_variable

* add uncombined_weight_to_state_dict API

* Remove paddle.incubate.hapi.loss and reuse the paddle.nn.layer.loss in high level API

* remove ProgramTranslator.save_inference_model

* adapt save_quantized_model

* revert buffer check implemention

* remove useless import function

* Refine Model

1. Take the network (instance of Layer) as the input of Model.
2. Refine set_dict/load_dict of Layer.
3. Refine Input interface, so update code sample about Input