Refactor param initialization from model manipulation to layers logic
Refactor param initialization from model manipulation to layers logic

Summary: This diff refactors the parameter initialization logic from model manipulation to layers

Reviewed By: azzolini

Differential Revision: D5920225

fbshipit-source-id: 50d230e406bc9ce0b00bdd164802c504cf32ea46

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