fix(timeouts): fix an obscure cause of firefox timeouts

Fixes #493
chore(release): version 0.18.0 changelog and version bump
feat(runner): add adapter for cucumber.js

Conflicts:
	lib/runner.js
Revert "feat(runner): add adapter for cucumber.js"

This reverts commit 88c339fc1d392717a0a5b8265806934b40158c5f.

Reverting for a clean release and to avoid force pushing.
fix(cli): specs was being processed as a string, not a list

Fixes #495
chore(release): version and changelog for 0.18.1
Revert "Revert "feat(runner): add adapter for cucumber.js""

This reverts commit 21e52a9faf0c2876146d90871eb377b1912e2e96.