[Speed] Refine elementwise sub,div,min,max gradient functor

Add capi-noavx-openblas download link

* Add profiling information for inference example, recognize digits.

* Refine the profiling method.

* Correct the use of RecordEvent and simplify recognize_digits.

add timeline profile howto

Add guide for howto documentation

* compile and install the static library of fluid inference

* fix dynload_cuda not in CPU mode

* update shared library and adjust the deploy of openblas

* adjust the deploy of openblas

* * auto add all fluid modules for static library
* use libprotobuf.a instead of libprotobuf-lite.a for profiler

* use set_property to set the global varible instead of ENV

* add gpu depends of fluid modules, auto add inference_lib_dist depends

* change the condition of openblas_lib, and fix a typo

refine operators/math/CMakeLists.txt

add print_log to memory_optimize

Make vec<Tensor> can be serialized to RecordIO

Refine concat_op

* MKLDNN conv2 OP kernel added

* TODOs added

* mkldnn conv2d OP refactor

* CanCUDNNBeUsed and CanMKLDNNBeUsed moved

Extract create_reader_op to three files

Removes Accuracy

fix a bug in backward

[Speed]Refine elementwise_mul_op

* test cpu float16 data transform

* add isnan etc

* small fix

* fix containsNAN test error

* add data_type transform GPU test

* add float16 GPU example

* fix error

* fix GPU test error

* add context wait

* Redesign channel implementation for Select Op

* Remove unecessary header

* Remove unnecessary comments