Refactor - Drop commonjs syntax

[b-ma]

Fixes #175 (...and #26)

Kind of the JS equivalent of #156 , should not have visible impact for users but cleans many messy workarounds that implies lots of structural changes

[b-ma]

  RESULTS:
  - # pass: 5108
  - # fail: 471
  - # type error issues: 0
> wpt duration: 3:10.975 (m:ss.mmm)

Improvements due in most part to the wpt submodule update