Webpack3 + ES6 Exports

[ryan-roemer]

This PR modernizes the Victory build and offerings. Generally:

• Provide an es/ directory alongside lib/ that has ES module export / imports (but everything else babel built) per the redux model. This model allows webpack2+ to use ESM resolution and enable tree-shaking, while is still backwards compatible with webpack1 which will use lib/
• Remove all references to .jsx since we don't use those anymore.
• Clean up and hone down a lot of stuff.

/cc @boygirl @chrisbolin

Cross-reference PRs

First, infrastructure:

• Webpack3 + ES6 Exports builder-victory-component-dev#7
• Webpack3 + ES6 Exports builder-victory-component#92

Second, core:

• Webpack3 + ES6 Exports victory-core#266

Third, dependers:

• Webpack3 + ES6 Exports #149
• Webpack3 + ES6 Exports victory-chart#495

Finally, parent:

• Webpack3 + ES6 Exports victory#651

Tickets

Implemented / fixed:

• Provide es6 build to use with Webpack. Fixes Provide es6 build to use with Webpack 2 victory#256
• Provide efficient webpack helpers for tree-shaking + DCE. Fixes Provide efficient webpack helpers for tree-shaking + DCE victory#548

Opened / still open:

• Webpack tree shaking does not completely remove unused re-exports. Webpack tree shaking does not completely remove unused re-exports victory#549

Bundles

The main goal here is not the victory bundle, but enabling webpack2+ users to get more efficient builds going off the es/ directory. And with the dedupe plugin being removed in webpack2+, our dev bundle is definitely bigger. But, fortunately, the prod minified bundles aren't that different:

Before / webpack1

$ find ../victory*/dist -type f -exec wc -c {} \;
  993198 ../victory-chart/dist/victory-chart.js
 1323555 ../victory-chart/dist/victory-chart.js.map
  438868 ../victory-chart/dist/victory-chart.min.js
 2634923 ../victory-chart/dist/victory-chart.min.js.map
  659513 ../victory-core/dist/victory-core.js
  915723 ../victory-core/dist/victory-core.js.map
  276427 ../victory-core/dist/victory-core.min.js
 1734458 ../victory-core/dist/victory-core.min.js.map
  674687 ../victory-pie/dist/victory-pie.js
  836742 ../victory-pie/dist/victory-pie.js.map
  284790 ../victory-pie/dist/victory-pie.min.js
 1814890 ../victory-pie/dist/victory-pie.min.js.map
 1013340 ../victory/dist/victory.js
 1235399 ../victory/dist/victory.js.map
  450323 ../victory/dist/victory.min.js
 2747731 ../victory/dist/victory.min.js.map

After / webpack3

$ find ../victory*/dist -type f -exec wc -c {} \;
 1663000 ../victory-chart/dist/victory-chart.js
 1602704 ../victory-chart/dist/victory-chart.js.map
  434851 ../victory-chart/dist/victory-chart.min.js
 3349108 ../victory-chart/dist/victory-chart.min.js.map
  975040 ../victory-core/dist/victory-core.js
  941706 ../victory-core/dist/victory-core.js.map
  265075 ../victory-core/dist/victory-core.min.js
 1930341 ../victory-core/dist/victory-core.min.js.map
 1219152 ../victory-pie/dist/victory-pie.js
 1092945 ../victory-pie/dist/victory-pie.js.map
  304427 ../victory-pie/dist/victory-pie.min.js
 2396990 ../victory-pie/dist/victory-pie.min.js.map
 1869374 ../victory/dist/victory.js
 1680468 ../victory/dist/victory.js.map
  487115 ../victory/dist/victory.min.js
 3846520 ../victory/dist/victory.min.js.map