Update bilstm integer array sorting example (apache#12929)

* Update the bilstm example to Gluon

* Update formating

* Update example/vae/VAE_example.ipynb

Co-Authored-By: ThomasDelteil <thomas.delteil1@gmail.com>

example/bi-lstm-sort/README.md

@@ -1,24 +1,14 @@
-This is an example of using bidirection lstm to sort an array.
+# Bidirectionnal LSTM to sort an array.
 
-Run the training script by doing the following:
+This is an example of using bidirectionmal lstm to sort an array. Please refer to the notebook.
 
-```
-python lstm_sort.py --start-range 100 --end-range 1000 --cpu
-```
-You can provide the start-range and end-range for the numbers and whether to train on the cpu or not.
-By default the script tries to train on the GPU. The default start-range is 100 and end-range is 1000.
+We train a bidirectionnal LSTM to sort an array of integer.
 
-At last, test model by doing the following:
+For example:
 
-```
-python infer_sort.py 234 189 785 763 231
-```
+`500 30 999 10 130` should give us `10 30 130 500 999`
 
-This should output the sorted seq like the following:
-```
-189
-231
-234
-763
-785
-```
+![](https://cdn-images-1.medium.com/max/1200/1*6QnPUSv_t9BY9Fv8_aLb-Q.png)
+
+
+([Diagram source](http://colah.github.io/posts/2015-09-NN-Types-FP/))