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 Minor inconsistency in config #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 Add registry of component modules #845
• drop Plotly.relayout handlers for the 'remove' and 'add' special values - see Consistent container update / removal  #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 c0eb065)