Fixing polling interval reset on window resize

Fixes #1726

Aha! That was the missing `clearInterval`. There is a custom function that gets called on resizing the window that also re-renders the graphs and resets the polling interval. It is there that the polling interval needs to be cleared. 

Actually I think that was the funky behavior I noticed when I added the clearInterval on document load (previous bug fix). I didn't make the connection that it was being caused by resizing the window.