* "fix decode bug"

* "follow commnet"

* "fix error"

* "fix hook bug"

* fix based comment

* fix copyright

* fix based on comment

Add distribution implement of image classification

* add split selected rows op

* update comment

* add grad check

* registry cuda kernel

* fix ci failed

update doc and dist test due to API change https://github.com/PaddlePaddle/Paddle/pull/7619#pullrequestreview-89656079

* Fix ParallelDo not support empty input gradient

* Polish ParallelDo and fix several bugs

* Fix CI

* Fix CI

1. Allocate memory for output before compute.
2. Rename 'ctc_decode' to 'ctc_align'

1. Remove 'top 1'(or argmax) from CPU and GPU kernel
2. Add a new test case
3. Refine doc

* add copyright hook

* add copyright hook

* refine copyright hook

* "test copyright hook"

* fix check style

* fix ci

1. Fix kernel
2. Add more test case

* "unified operators"

* "add CUDNN register"

* "add use cudnn attribute"

* "add attribute"

* "test conv tranpose op"

* "remove duplicated attr"

* "fix op test"

* "add attribute to set cudnn"

* "add more log"

* "need layout op register support"

* "add more log"

* "change GetExpectedKernelType "

* "fix Get attr in conv_op"

* "fix CI"

* "fix tests"

* "removed kernel priority fallback"

* "fix CI"

* "fix stack pointer bug"

* "refine buggy interface"

* "add const cast to save life"

* "fix get_output_with_grad"

* "fix op test with dataformat"

* ""fix pooling

* "fix pooling test"

* "fix CI"

* "fix with_gpu error"

* "add transform needed functional check"

* "fix unpack list error"

* "comment out parallel.do temporary"

* "fix CI"

* "fix compile doc error"

* "make threshold larger"