Support Scatter charts

[jithine]

First of all thanks for this amazing library. Would it be possible to add Scatter type charts to existing supported ones? http://www.chartjs.org/docs/latest/charts/scatter.html

[intrueder]

@jithin1987
From docs,

To use a scatter chart, data must be passed as objects containing X and Y properties

That's all you need.

[kumarharsh]

@intrueder yes, that makes sense. But while translating chartjs directly to react code, I was expecting this to work:

import { Scatter } from 'react-chartjs-2';

Which would have been equivalent to what you write in vanilla js: var scChart = Chart.Scatter(canvas, {...}).

Chart.Bar, Chart.Line, etc are exposed, so why not Chart.Scatter too? Just to be clear, I don't have a big problem with using Line for scatter chart per se, but for clarity and equivalence with chartjs API, it might be a good to have...

[kumarharsh]

FYI, there are some more settings involved for rendering a proper scatter chart using line charts. Refer to the defaults in this PR: chartjs/Chart.js#4381