Add an implicit MessagePort to ServiceWorkerGlobalScope
Remove historical cruft. Everyone (TM) knows what a Promise is.
Move Request.prototype.url to a string. Fixes #154.
Move CacheList to an AsyncMap. Refs #142
Move `CacheList` to be async. Fixes #142
Merge pull request #153 from jungkees/typescriptupdate

Add an implicit MessagePort to ServiceWorkerGlobalScope