... to avoid confusion with Array.isArray and upcoming
    Lib.isTypedArray

... and use typed array 'subarray' to slice coordinate arrays
    to series length

... that should accept typed array (mostly arrayOk attribute,
    with marker.size and marker.color being to most likely
    candidates for typed array inputs).

- do the Lib.extend* methods do the right for typed arrays
- what to do with 2d arrays? Should we start supporting ndarrays?
- should we invent a JSON-seriliazable version of typed arrays?

... replot is sufficient since regl push.

... to make things look a little more like
    the rest of plotly.js

- reuse scatter axis-expansion logic
- improve 'fast' axis expand routine (using average marker.size
  as pad value)
- use ax.makeCalcdata for all axis types (this creates a new array
  for linear axes, but makes thing more robust)
- add a few TODOs

- most notable change is in gl2d_axes_label2 that
  now shows the correct to-zero autorange.

... by merging the concat and splice steps (which can't
    be done using native methods on typed arrays)

On-par autorange for scattergl

- by making sure it returns false on instances of DataView

... for now.

- we could have used isNaN here, but isNumeric is fast enough
  that the gains would be negligible.