Misc. plugin bug fixes

[texodus]

• Added adaptive scaling to scatter charts with the "Size" column set, calculating a scale factor for container sizes from 800px -> 1600px to minimize visual crowding.
• Fixed persistence and reset() adherence of the aggregates attribute, which was omitted previously.
• Fixes side panel overflow, e.g. column names gaining ellipsis and not overlapping the plugin, which was broken in New plugin api #1457
• When a column is configured in "Bar" style, it has a CSS min-width of 50px imposed which now no longer causes the auto-width feature to expand when "Bar" is deselected.
• <perspective-viewer>'s save() method now returns less data in the plugin_config key for all plugins; in previous versions some data columns were accidentally included in this key, and while innocuous, they inflate the token size considerably.
• Fixed "Treemap" and "Sunburst" dimensions when column-pivots are present, so more sub charts are visible on screen at a time.
• Fixed race condition in restpre() which caused columns to be overridden with plugin-defaults.
• Fixed styleElement() method which was removed in New plugin api #1457, and changed its behavior to apply to all registered plugins (rather than just the visible one).
• Fixed perspective-viewer-d3fc chart axis and legend interactions, which caused the renderer to draw a white plane until the config is changed, which was regressed in New plugin api #1457