Upgrade Flot Charts

[aalpern]

Miraculously, the Flot charts project is under active development again! (see http://www.flotcharts.org/blog/2018/02/04/flot-216-new-maintainers/). Upgrade to the latest version. This will likely require a bunch of changes.

• https://github.com/flot/flot
• https://www.flotcharts.org/
• https://www.npmjs.com/package/flot

Things that are likely to require changes:

• Default time base of seconds, not millis: Backward compatibility flot/flot#1612. May need to add timeBase: "milliseconds". See https://github.com/flot/flot/blame/master/CHANGELOG.md#L43
• autoscale renamed to autoScale
• various series options are now in a series sub-object. See https://github.com/flot/flot/blame/master/CHANGELOG.md#L20
  • flot-barnumbers needs updating
• the d3 stacking plugin no longer works - that will require some updating
• time and axislabels plugins now baked-in
  • converted tick formatter to a plugin
  • Could look at using the new jquery.flot.absRelTime.js plugin (more flexible time formatting), which allows for time format specification as well, which would handle Make time axis label formatting configurable #451
• New logaxis plugin - does it change how log axes are specified?
• Axis labels are messed up in tessera's charts
• hover-over series highlighting causes weird rendering errors when axis labels are present
• time series bar charts are rendering incorrectly
• pie charts are not rendering at all
• "- move backgroundColor and backgroundOpacity from legend settings to css" - might affect color themes
• Update themes CSS to include axes, which are SVG now. https://github.com/flot/flot/blame/master/CHANGELOG.md#L76
• Hover over is broken for pie charts (See Pie chart plothover fires extra events with null item flot/flot#1645, currently in progress)
• Hover over is broken for discrete bar charts
• Rendering error on horizontal discrete bar charts
• Series highlighting doesn't work for time series bar charts, but I think that never worked