Validate input in socket callbacks
Ghost multiple session connections

Multiple connections could be made from the same session,
which could cause issues when they disconnected in turn.
"use strict";
Remove definedness chart

The new parsing system is robust enough to eliminate its persistent need
Faint backgrounds for each column

Also push vis-hide structure up to contain the columns, rather than each
column having its own vis-hide div
White chart backgrounds, pad userlist
Restructure trellis-chart DOM, add separators
Add domain labels to trellis chart

Massive cleanup of margins and offsets.