Should we add a `Plotly.update` method?

[etpinard]

that could update both data and layout at the same time?

Something like:

/**
 * @param {string or HTML element} gd
 * @param {object} traceUpdateObj update object as in Plotly.restyle
 * @param {object} layoutUpdateObj update object as in Plotly.relayout
 * @param {array} traceIndices list of indices as in Plotly.restyle
 */
Plotly.update = function(gd, traceUpdateObj, layoutUpdateObj, traceIndices) { 
  // ...
};

I'm sure that would make folks like @chriddyp, @VeraZab and @armintaheri happy.