Deprecate usage of d3 for scatter plots

[nicbarker]

At the moment, using d3.js to render our scatter plots is very unperformant. It may be possible to use it just to render the axis (which is still very useful). We're actually rendering the points using canvas at the moment, but the point positions is still calculated using d3, and even calculating and iterating through the points without rendering them puts significant load on the cpu. I suspect that transitioning to a completely canvas based solution will give us the necessary speed.