browser freezing problems

[sgowda]

Usually after bad task crashes the browser freezes, and a refresh doesn't bring the page back. You have to restart the Django server and then reload the browser page.

1. figure out if this is a javascript error or a python error (it should be a python error since the reload should reset the javascript state)
2. check if the tornado webserver has crashed
3. try to make the task crashes more graceful for the tornado webserver