* fix conflicts

* fix kernel registry realted bugs test=develop

* code clean - refine ARM

cmake enhancement:

- add lite_cc_library and lite_cc_test

code clean:

- remove ARM feed and fetch kernels, reuse the Host's

remove unnecessary comments

test=develop

test=develop

make typesystem simpler

* reset drop local scope counter
test=develop

* Add conv2d_grad_grad_op
* Extracte the cuDNN conv algo searching code in conv_cudnn_helper.h.
    - Now use it in conv2d_grad_grad.
    - Will simply the searching code in conv2d and conv2d_grad in next PR.
* Enhance and fix bug in unit testing of gradient_checker.
* Support to fetch empty variables，return None in Python.

test=develop

* fix train_from_dataset and infer_from_dataset example

* add inductive dim for data_reader, example: shape=[-1, 1], then -1 will be inducted through run-time reading of number of elements

test=develop

* fix shape_check; test=develop

* fix format; test=develop

* fix format; test=develop

* fix ddim bug; test=develop

* fix c++ format; test=develop

* change function name; test=develop

* move pass to ir

* polish code
test=develop

* fix dependency
test=develop

* add use_cuda to inplace pass,test=develop

* add test softmax_with_xe_inplace test,test=develop

* fix potential inplace bug
test=develop

* add more skip vars in mem opt pass,test=develop

* follow comment,test=develop

* follow comments,move duplicate out arg check to program->graph,test=develop

integer', test=develop

* cherry-pick commit from 88770542

* cherry-pick commit from 3f0b97df

* cherry-pick from 16691:Anakin subgraph support yolo_v3 and faster-rcnn

(cherry picked from commit 8643dbc2)

* Cherry-Pick from 16662 : Anakin subgraph cpu support

(cherry picked from commit 7ad182e1)

* Cherry-pick from 1662, 16797.. : add anakin int8 support

(cherry picked from commit e14ab180)

* Cherry-pick from 16813 : change singleton to graph RegistBlock
test=release/1.4

(cherry picked from commit 4b9fa423)

* Cherry Pick : 16837 Support ShuffleNet and MobileNet-v2

Support ShuffleNet and MobileNet-v2, test=release/1.4

(cherry picked from commit a6fb066f)

* Cherry-pick : anakin subgraph add opt config layout argument #16846
test=release/1.4

(cherry picked from commit 8121b3ec)

* 1. add shuffle_channel_detect

(cherry picked from commit 6efdea89)

* update shuffle_channel op convert, test=release/1.4

(cherry picked from commit e4726a06)

* Modify symbol export rules

test=develop

* add use_cuda to inplace pass,test=develop

* add test softmax_with_xe_inplace test,test=develop

test=develop

* fix bn fuse vardesc and add model saver

test=develop

* unify save model in test helper

test=develop

* fix mkdir on windows

test=develop

* remove magic number use bn bias var desc

test=develop

* fix op graph view
test=develop

* rewrite inplace pass and fix reference count pass bug
test=develop

* fix unittest failed
test=develop

* follow comments, test=develop

test=develop

test=develop

test=develop

test=develop

* Add fuse momenutum ops

test=develop

test=develop

* speedup gc and inplace softmax_with_cross_entropy_grad
test=develop

* refine models gpu mem
Merge skip vars and warning messages of mem opt
remove relu mem opt
test=develop

* follow comments
test=develop

* Support seq len equal to 0 in sequence ops

test=develop

* Add more test cases

* Fix some comments

test=develop

* Fix py3 error

test=develop

test=develop