Allow multiple widgets on a single page

[mockenoff]

Web sockets don't allow multiple connections to the same port because, well, duh. Using the facility option with django-websocket-redis makes it a lot easier to silo off messages, but it can't support multiple bracket updates on a single connection.

The solution will most likely involve doing independent group tracking per client within Redis on the JunctionView request methods.

[mockenoff]

Turned out to be simpler by handling the multiple embeds on the front end and iterating through "cached" container node selections.