Add nccl context pybind

Fix dygraph checkpoint bug

use multi-thread to speedup CI tests

Fix test_profiler when the machine has many cores.

Refine ENFORCE in infer_shape of gru_op and lstm_unit_op.

fix logical op infershape

disable test_elementwise_mul_mkldnn_op case

imperative fix tracer train mode

test=develop

* fix sampling id op bug, test=develop

Improve preprocessing script and read from tar

* fix overflow by int32 mul test=develop

* fix reference nullptr

* fix codestyle test=develop

* modify to point in ContextProjectFunctor test=develop

* modify to point in ContextProjectFunctor test=develop

* modify . to -> test=develop

fix infershape bug

test=develop

Fix infer shape of split lod tensor op

fix teacher_student op infer

Fix bpr loss

separate runtime infershape

fix shape check many by hongyu

test=develop

modify infer shape pad_op, pad_constant_like_op, no need in psroi_pool_op, crop_op

* fix infershape in runtime

* fix infershape in runtime
test=develop

* fix infershape in runtime

softmax cross entropy support high rank

test=develop

polish yolov3_loss annotation

move split filelist from trainer.py to fleet & fix error

test=develop

Fix yolo param

test=develop

test=develop

test=develop