remove unused code and fix typo

Fix GPU Compile on Linux

* add lstm layer

* set hidden shape

* rename input parameter

* add dynamic lstm

* refine dynamic lstm layer

* change parameter using XavierInitializer by default

* refine dynamic lstm layer

* create learning rate variable for every parameter

* fix ci

* set parameter lr relatively to global lr

add resize of MKLDNNMatrix

* "fix ci failed"

* "comment out seq_concate op to unblock PRs"

Add expand operator

TensorSetConstant struct is used both in math_function.cc and math_function.cu. Somehow the release version can correctly handle it. But in debug version, set_constant_with_place() in math_function.cu uses the TensorSetConstant in math_function.cc and causes crash.

it is useful in gradient phase of an operator with block

It caused by a bug of std::call_once described in https://stackoverflow.com/questions/41717579/stdcall-once-hangs-on-second-call-after-callable-threw-on-first-call. It is likely caused by a deeper bug of pthread_once, which is discussed in https://patchwork.ozlabs.org/patch/482350/

add ROIPooling for Fast(er) R-CNN

fix openblas bug: undefined reference to pthread_atfork

update mkldnn design doc

* fix seq_concat with refactaring LoD

* fix failed unit test

* rename function name

add API for copying data from/to paddle matrix

IndicateDataType --> GetKernelType

fix typo in faq.