Fit google C++ style

Make code more clearer

Implement EigenCudaStreamDevice

use param header to save mkldnn format info

* Clone method will create a new object instance, which is as same as
  itself.
* This is the first step to remove shared_ptr for OperatorBase

* add clang-format with version check 3.8

* improve doc

* insert rnn's backward into Backward()

* add device_context into backward_test

* large model train note

* update

* update doc

fix crash when disable WITH_SWIG_PY

build documentation don't need install Paddle before

Fix local recordio reader

add shared mkl lib in whl

* make stepnet member

* add pybind support

* fix Inputs Outputs

* remove unique_ptr

change operator public to protected

scatter update implemented

Replace `EmptyOp` with `NOP`

simplify docker script

Merge maps in OpRegistry and simplify register macros