Allow explicit domains on ordinal axes

[jwildfire]

The following settings:

x: {
  type: 'ordinal',
  domain: ["Scrn", "D1", "D4", "D8", "D29", "D32", "D36", "D50", "D121", "D212", "D394"],
  ...
}

only gives a chart showing bars for the current data, and can ignore several of the specified domain levels if data is sparse:

But, this simple callback:

        chart.on('init', function() {
            chart.config.x.domain= ["Scrn", "D1", "D4", "D8", "D29", "D32", "D36", "D50", "D121", "D212", "D394"]
        });

gives the desired behavior: