chart type only showing dots

[biovisualize]

Just a quick example to expose that we can make a dot chart, following an idea from @venk-at-krishnamurthy

Venkat Krishnamurthy [01:41] http://software.es.net/react-timeseries-charts/#/example/wind would be great to add these or similar time series viz types at some point

For now the config is:

{
    chartType: dot,
    dotsToShow: "all"
}

There's no way to test it for this PR than to try it on a local branch. But the code is probably simple enough to show that it has a limited capacity to cause side-effects.

[clhenrick]

@biovisualize do you mean for this to be a scatterplot? Assume if that's the case we would have to support string values for both the x and y axises & scales.

[biovisualize]

No, it's just a time series dot plot as in the example linked above.