wishlist for potential breaking changes since v1

Leave this text box for planned improvements

• upgrade d3 to v4.0.0 (now v5) - should be mostly a matter of updating the general update pattern.
• remove es-promise polyfill from bundle - and thus make IE users add their own Promise polyfill.
• drop jQuery event support
• Make components (e.g. Annotations, Shapes, RangeSlider, …) register-able and remove them from the core bundle.
• revamp set of default colorscales
• make config arguments consistent https://github.com/plotly/plotly.js/issues/839
• remove config.plot3dPixelRatio map for backward compatibility
• Incorporate /remove all unofficial exposed methods (i.e Plotly.Plots, Plotly.Fx, Plotly.Snapshot, Plotly.PlotSchema, Plotly.Queue)
• drop event-based Plotly.Snapshot.toImage and merge src/snapshot in plot_api/to_image.js
• remove (some) components for lib/core.js - see https://github.com/plotly/plotly.js/pull/845
• drop Plotly.relayout handlers for the 'remove' and 'add' special values - see https://github.com/plotly/plotly.js/pull/1086
• for log axes, have layout express everything in data units instead of linearized units. This applies to range, tick0, and annotation and image positions.
• remove support for dates provided as epoch milliseconds
• remove the distinction between axis name and axis id (ie xaxis2 vs x2) probably by only using the name.
• rename current gl marker symbol 'cross' -> 'cross-thin' (i.e. revert https://github.com/plotly/plotly.js/pull/1482/commits/c0eb06599db481f2137ed97e79bab5cb2bc31351)

[etpinard]

On my list:

• Incorporate /remove all unofficial exposed methods (i.e Plotly.Plots, Plotly.Fx, Plotly.Snapshot, Plotly.PlotSchema, Plotly.Queue)
• Use proper state object instead of storing state in graph DOM element.
• Add OO API e.g :

var plot = Plotly.createPlot('graph', data, layout, config);

plot.restyle(/* */);
plot.relayout(/* */);
plot.resize();
// ...

• Drop jQuery event support
• Better, more-consistent events data
• Better, more-consistent config options

[etpinard]

Remove our es6-promise polyfill and ask IE9, IE8, IE11 (ref) to use their own Promise polyfills.