Refactor on webpack config

[diegohaz]

Adds webpack-blocks-split-vendor and webpack-blocks-happypack to simplify webpack config.

[codecov-io]

Codecov Report

Merging #211 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master   #211    +/-   ##
======================================
  Coverage     100%   100%            
======================================
  Files           2     40    +38     
  Lines          95    275   +180     
  Branches       36     54    +18     
======================================
+ Hits           95    275   +180

Impacted Files	Coverage Δ
src-clean/components/index.js
src/components/atoms/Button/index.js	100% <0%> (ø)
src/components/templates/PageTemplate/index.js	100% <0%> (ø)
src/components/atoms/TableCell/index.js	100% <0%> (ø)
src/components/molecules/Table/index.js	100% <0%> (ø)
src/components/atoms/Heading/index.js	100% <0%> (ø)
src/components/organisms/Hero/index.js	100% <0%> (ø)
src/components/organisms/Footer/index.js	100% <0%> (ø)
src/components/organisms/FeatureList/index.js	100% <0%> (ø)
src/components/pages/GenericPage/index.js	100% <0%> (ø)
... and 30 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fa36a81...632466d. Read the comment docs.

[diegohaz]

It'll also help with things like #188 (it's easier to add that functionality)