SINGA-349 Create layer operations for autograd
SINGA-349 Create layer operations for autograd

1.Implemente some layer operations by packaging Pylayer.
These layers is runnable.

2.Change the location of layer_ops to python/singa

apache/incubator-singa,nusdbsystem/incubator-singa,kaiping/incubator-singa,nudles/incubator-singa,nudles/incubator-singa,nusdbsystem/incubator-singa,kaiping/incubator-singa,ijingo/incubator-singa,apache/incubator-singa,apache/incubator-singa,kaiping/incubator-singa,nusdbsystem/incubator-singa,nusdbsystem/incubator-singa,ijingo/incubator-singa,ijingo/incubator-singa,ijingo/incubator-singa,apache/incubator-singa,kaiping/incubator-singa,nudles/incubator-singa,nudles/incubator-singa,apache/incubator-singa,nudles/incubator-singa,kaiping/incubator-singa,nusdbsystem/incubator-singa,ijingo/incubator-singa