*  Add shufflenetv2 in test_libs demo, test=develop

* fix cuda demo. test=develop

* update type error. test=develop

* add train_demo, test=develop

* Ehance mobilenetv1/v2, add std_dev computation. test=develop

* Ehance cxx mobile_light demo, add std_dev computation. test=develop

* [LITE][OPENCL] Change fp32 fc to fp16's. test=develop

* fix act in conv3x3opt opencl kernel. test=develop

* [LITE][CMAKE] fix cmake for opencl tiny_pubish compile. test=develop

- 增加cuda c++ demo.
- 考虑到检测模型尾部一般是multiclass_nms，该kernel为host，如果fetch kernel为cuda的话，则会在此处插入无用的io_copy(host->cuda)，由于该原因，注释掉fetch的cuda kernel. 默认使用host的fetch kernel. 此处暗中进行的行为：每次predictor run完，都会默认把数据从cuda拷贝到cpu

* improve conv_dw profile with rel relu6 leakyrelu, test=develop

* add depthwise, test=develop

* fix ci error, test=develop

* fix cv demo print, test=develop

* [LITE][OPENCL] Change fp32 fc to fp16's. test=develop

* fix act in conv3x3opt opencl kernel. test=develop

* [LITE][DEMO] fix input arg. test=develop

* fix shutdownlog for std::endl. test=develop

* [LITE][DEMO] Enhance mobile_light demo. test=develop

* fix print. test=develop

* fix clang v7 error
* change ut, test=develop
* fix conv ut, test=develop

* fix

* fix format. test=develop

* fix format, test=develop

* fix resize error

* fix format. test=develop

* fix format, test=develop

* fix format

* note log(4) << x_image. test=develop

* note x_image printf. test=develop

* fix leakyrelu and tanh compute error, test=develop

* delete extra file, test=develop

* reset act

* fix conflict and readme, test=develop

* fix ios run error, test=develop

update mask detection demo

* make full_publish to fix link bug in mask demo

Update mask demo docs, add model download from paddlehub

* [DEMO] add mask detection demo, test=develop

* [DEMO] fix ssd detection demo bug, test=develop

* FIX CXX DEMO MAKEFILE TO SUPPORT MAC COMPILE test=develop

* test=develop

* add cv image process

* fix arm liunx build error

* add LITE_WITH_CV defien to make cv, test=develop

* fix cv format, annd add describe in utils/cv

* set LITE_WITH_CV=OFF in build.sh, test=develop

* delete cv_enum.h in utils/cv, push the contents in cv_ennum.h to paddle_image_preprocess.h, test=develop

* according to reviews to redefine paddle_image_preprocess.h, test=develop

* add detailed note of flipParam, test=develop

* fix format in paddle_image_preprocess.h, test=develop

* fix cmake error in llite/CMakeLists.txt, missing mkdir cxx, test=develop

* according to review change, test=develop

* add elemetnwise mul constant elimination and deconv+relu, deconv+batchnorm fusion, test=develop

* fix format, test=develop

* fix model_optimize bug, update concat and split op, speed up, test=develop

* update split speed, test=develop

* fix format, test=develop

* add classify demo inn demo/cxx/ , test=develop

* fix formart inn mobile_classify, test=develop

* delete some note and extra code, test=develop

* remove test.jpg and labels.txt, test=develop

* add test_cv in cxx/demo

* add test_cv READMEE, test=develoop

* add note info, flip only support x, y, xy;rotate only support 90, 180, 270; test=develop

* fix build error, paddle_cv_arm , test=develop

* add GRAY to RGBA(BGRA) convert and RGBA(BGRA)_to_Tensor, test=develop

* fix format from review, test=develop

* fix makefile format. test=devellop

* fix bbuuild v7 error, test=develop

* [Demo] add cxx mobilenetv1-ssd detection demo, test=develop

* add makefile to mobile detection demo, test=develop

* [Demo] add cxx mobilenetv1-ssd detection demo, test=develop

* [demo] fix mobile_detection code style, test=develop

* [Demo] fix demo code style, test=develop

* [Demo] fix detection demo makefile dependency, test=develop

* Add CheckInput. test=develop

* Fix android_log_ undef when using .a. test=develop

* add guide of how to use shared library in demo. test=develop

* Fix bug target for kHost and kARM not equal. test=develop

* Fix license. test=develop

* add debug -g option. test=develop

* enable opencl demo. test=develop

* Fix model_optimize_tool found no opencl kernel. test=develop

* add more vlog. test=develop

* remove macro LITE_WITH_OPENCL, LITE_WITH_FPGA in passes. test=develop

* Fix valid_places in mobilenetv1_test. test=develop

* Fix bug of find no real output of fetch, after tool OPs of optimzer passes. test=develop

* Fix vlog as log message in model_optimize_tool. test=develop

* fix miscs. test=develop

* fix comment. test=develop

* Fix misspell of opencl, fpga kernels name in lite/api/CMakeLists.txt. test=develop

* add opencl macro in full_api of demo. test=develop

Fix compiling bug in android_armv7_demo : cxx demo can not compile properly because demo' android version is different from that of library file (#2308)

link armv7 demo to android-23 to make sure the demo can compile properly
cxx demo can not compile properly because demo' android version is different from that of library file, we fix this bug by linking armv7 demo to android-23