add assign,equal,fill_constant_batch_size_like,range,reduce_prod,cond…  … …itional_block cpu op (#1783)

* add assign,equal,fill_constant_batch_size_like,range,reduce_prod,conditional_block cpu op

* 1.fix roi_perspective_transform,lod_reset,multiclass_nms,slice,while op
2.elementwise_add compute support int input
3.scale compute support int64_t input

* 1.add slice, exp, leakyrelu, nearest op placeholder. 2.complete slice and exp op. 3.fix sigmoid op.

* fix style

* add slice cpu op

* print error var name && print op position