Revert "Merge pull request #358 from ayg/submission/ayg-use-webidl2"

This reverts commit d4dbf977ec2460eda4af57434b795069aaf62948, reversing
changes made to d2a10f31b00df85aa0a4f8b242785d838f82f788.
Merge pull request #363 from tobie/revert-pull-request-358

Revert "Merge pull request #358 from ayg/submission/ayg-use-webidl2"