Add Reduction layer in caffe_translator
Add Reduction layer in caffe_translator

Summary:
Caffe's Reduction corresponds to Caffe2 ReduceBack*. Added a translator for
stephenyan1231's model.

Reviewed By: stephenyan1231

Differential Revision: D4848289

fbshipit-source-id: 7cb61c115549ffa6be8d0c19a5eaed99c3c086b6

davinwang/caffe2,bwasti/caffe2,Yangqing/caffe2,davinwang/caffe2,davinwang/caffe2,sf-wind/caffe2,Yangqing/caffe2,Yangqing/caffe2,bwasti/caffe2,davinwang/caffe2,pietern/caffe2,sf-wind/caffe2,bwasti/caffe2,sf-wind/caffe2,caffe2/caffe2,bwasti/caffe2,sf-wind/caffe2,xzturn/caffe2,bwasti/caffe2,Yangqing/caffe2,pietern/caffe2,pietern/caffe2,xzturn/caffe2,sf-wind/caffe2,davinwang/caffe2,xzturn/caffe2,xzturn/caffe2,xzturn/caffe2,Yangqing/caffe2,pietern/caffe2,pietern/caffe2