refactor: apply webpack-defaults

[joshwiens]

Intended to be merged as a part of 1.0.0 on a beta dist-tag once this has been finished and properly tested.

Further refactoring and test fixes are required to align with the defaults.

BREAKING CHANGE:

Enforces NodeJS > 4.3 via engines

Closes #56

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@d2c7218). Click here to learn what that means. The diff coverage is 45.13%.

@@            Coverage Diff            @@
##             master      #55   +/-   ##
=========================================
  Coverage          ?   45.13%           
=========================================
  Files             ?        4           
  Lines             ?      144           
  Branches          ?       44           
=========================================
  Hits              ?       65           
  Misses            ?       66           
  Partials          ?       13

Impacted Files	Coverage Δ
src/cjs.js	0% <0%> (ø)
src/lib/transformer.js	36.36% <36.36%> (ø)
src/lib/conditions.js	55.55% <55.55%> (ø)
src/index.js	73.07% <73.07%> (ø)

---

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 d2c7218...92b0dc7. Read the comment docs.

[joshwiens]

This shouldn't have had the review label on it yet, sorry

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@d2c7218). Click here to learn what that means. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master      #55   +/-   ##
=========================================
  Coverage          ?   45.13%           
=========================================
  Files             ?        4           
  Lines             ?      144           
  Branches          ?       44           
=========================================
  Hits              ?       65           
  Misses            ?       66           
  Partials          ?       13           

---

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 d2c7218...92b0dc7. Read the comment docs.