Update dc submodule pointer
Broadcast active filters

There is now a simple node application to enable broadcasting of active
filters, using socket.io.

Currently, everyone on the server will send and receive all changes.
This might get chaotic depending on how crowded things become.
Perhaps `channels' might help keep things scalable.

Broadcasting filters for the stat trellis chart would be interesting.

You can also set and change your own nickname.

This closes #12.
Move served files to a public/ directory
Update documentation