add rpow & fix 'Number' to 'Number_' (#76)
add rpow & fix 'Number' to 'Number_' (#76)


jermainewang/nnvm,jermainewang/nnvm,piiswrong/nnvm,piiswrong/nnvm,imai-lm/nnvm,jermainewang/nnvm,ZihengJiang/nnvm,imai-lm/nnvm,imai-lm/nnvm,ZihengJiang/nnvm,piiswrong/nnvm,ZihengJiang/nnvm