* Add cpplint_pre_commit.hook

* Update hook

* Disable dropout_op_test.cc

* Remove cpplint.py but requires users to install their version

* fix cpplint error

Fix dist error with lr decay layer

* add prefetch_op

* fix ci

* optimize code

* optimize code

* fix include

* "add functors"

* "remove old code"

* "fix"

* "fix ci"

* "add details"

* "fix ci"

* "fix ci"

* "fix ci"

* "fix ci"

* "remove unused code"