Can't process Kernel Binary messages

[kjcho-msft]

Describe the bug
When kernel sends binary messages, nteract can't handle them correctly.

To Reproduce
Steps to reproduce the behavior:
Make sure you have nglview extension installed.

pip install nglview
jupyter-nbextension enable nglview --py --sys-prefix

Run the following:

from IPython.display import display
import nglview
view = nglview.demo()
display(view)

Expected behavior
nglview renders correctly

Observed
When you run the cell above, kernel sends Binary messages

and it causes the following error.
SyntaxError: Unexpected token 'o', "[object Blob]" is not valid JSON
at JSON.parse ()
at deserializer (WebSocketSubject.js:10:1)
at socket.onmessage (WebSocketSubject.js:178:1)