* exhaustive search for cuDNN conv.
* Refine code and add unit testing.
* Clean code
* Fix model load in fluid/inference and unit testing in conv2d
* Follow comments.

Fix rmsprop_op enforce bug

test=develop

fix jit on mac

Remove some locks in ParallelExecutor

Stream Callback Support in CUDA 10

run dist tests in serial

test=develop

test=develop

test=develop

* add dam test

* update fuse_statis

* use separated dam model.

* Revert "use separated dam model."

This reverts commit 13e775c8.

* test=develop

* modify the cmake file about infer test, test=develop.

* remove one comment, test=develop.

test=develop

Warning only at first when CUDA CC not matched.

test=develop

* Fix build error of affine grid op in mac os.
test=develop

* Make function return reference.
test=develop

Refine/jit/vmulcode

Fix lod_level share bug in read_op

* wip

* add ref_by_trainer_id op

* ready to test

* fix ref inputs

* refine rpc_op_handle

* fix merge bug

Residual data reorder in MKLDNN convolution

Fix avx illegal instuctions

throw error when mismatch cpu avx version

test=develop

test=develop

Fea/jit/gen

fix to only check block 0

test=develop

test=develop

test=develop

test=develop

"fix sign op"

Fix selected_rows clip bug

add more debug info.

test=develop

add inclusive/exclusive mode in avg pool

Grid sampler operator for spatial transformer network.