Max Sequence pool optimization

remove with_inference option

* feat(platform): lazy initialization of devicecontext in pool

Use std::async(deferer, []{...}) to lazy initialize DeviceContext in Pool

test=develop

* Add future includes

test=develop

increase test timeout coverage.

1.add position encoding  2.logloss in nn.py

Fix inference model not found on Mac CI

* fix sum_op's GetExpectedKernelType
test=develop

* fix ci fail
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generate proposal labels doc

Refine/jit/crf decoding

Fix import plot in py3

disable some tests

[1.1] fix cmake warning when ON_INFER=false

OrderSet default is mutableSet, not set.

fix xxhash compile on macos

[1.1] Cpu for 1.1 merge with shape

test=develop

- Added rough profiling

- Profiled maxpool itself

- First draft of max seqpool optimization (is_test added)

- Added unit tests to seqpool

- Cosmetic fixes

- Fix to UT of Seq pool

Disabled grad checking for sequence max pool when is_test is set to True

-Cosmetic fix to comment

test=develop

- Fix to GPU build

test=develop

- yet another GPU fix for sequence max pool

- Fix to comment

test=develop

- Change to API of sequence_pool

test=develop

- Yet another API spec change

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[1.1]Fix op_role value

test=release/1.1

test=develop

fix test resnet50 multi-threading on mkldnn

* fix nccl2 lars dist support

* put lars in momentum op

* add tests lars

* fix ci

* fix cpu kernel

* soft warning

* remove lars in test_recognize_digits.py

* move to another op

* add file

* update api.spec test=develop

* update test=develop

* fix api.spec test=develop

* wip

* wip, finish grad merge ops

* wip, finish graph build

* wip test running

* work on 1 gpu

* workable version

* update

* fix tests

* fuse broadcast op

* fix compile failed

* refine

* add batch merge test mnist

* fix CI test=develop

* fix build

* use independent bn params for batch merge test=develop

* update api.spec

* follow comments and for test

* wip

* refine tests test=develop

* follow comments test=develop

* remove startup bn modify test=develop

* follow comments test=develop

* fix merge test=develop

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delete unused codes.