* add mem opt option for high api ,test = develop

* fix is_lod params && test-performance ,test=develop

* fix useless init emptyimage , test = develop

1. improve n-fold quantification algorithm by introducing a minimal size for each fold. 2. automatically search for best n for n-fold algorithm. (#2167)

* 1. add quantification_fold parameter. 2. support quantification test in run.py.

* implement n-fold quantification

* open cl mem optimise, split with cpu codes.
fix a bug when some memory is not equal 4 .

* open cl mem optimise, split with cpu codes.   fix a bug when some memory is not equal 4  fix bad des

* get opencl kernel_work_group_size and set local_work_group_size for conv and conv_trans kernel of GAN, test=develop

* fix fpga CI error, test=develop

* fix fpga CI error, test=develop

* auto set local work group size according to devices

* Optimal OPENCL conv_trans_7x7 Performance , test=develop

* fix CI error, test=develop

* fix vector out of range crash test=develop

* fix style test=develop

* fix ios CPU preprocess test=develop

* fix style test=develop

* accelerate opencl compilation time test=develop

* fix style test=develop

* fix variant memory leak test=develop

* fix variant memory leak & fix style test=develop

* fix cpplint test=develop

* add opencl  depthwise_conv_trans_op

* test=develop

* Catch mobile exceptions test=develop

* code style format test=develop

* enable fast test compilation && push opencl kernels by run.py

* merge cl kernels into so

* restore pre-commit