* add gpu_timer to external function

* compiled version

* working version

* using block_begin and block_end

* add the missing '
;'

* move slice to cuda emiter

* change size_t to uint32_t in kernel

* working version

* change block size from 1 to 64

* fix bugs

* nthreads need to be size_t in broadcast op

* add rank to kernel name hash

* update slice in convolution

* resolve index conflict

* change align to align_to_blocksize, add overflow check

* add gird size check and fix pool merge bug

* code style, change names