Add stacked fused RNN example (#5186)
Add stacked fused RNN example (#5186)

* Add stacked fused RNN example

* Add parse option for stacked rnn

* Add missing warning messages

Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet,Guneet-Dhillon/mxnet