User Streaming fixes 

In this PR:

* Doesn't use local storage for the `connection_id` -- this was making more problems than it solved, especially with multiple tabs.
* Fixes fallback to polling when the socket either failed to connect, received an error, or was closed by the user (there's no way to do this now).
* Adds a green indicator light next to `#room_title .participants` when streaming is being used