caches.get and caches.create to caches.open
Oops, old docs
Merge pull request #3 from wibblymat/master

Fixed a bug with addAll not returning a Promise
Global crept in twice
Fail on opaque responses
Update build
Created a few race conditions that caused more match checking than needed (sometimes resulting in newer versions being used even if an older one was available).

FTR I hate how idb forces me into callback hell.
.match should reject if the request wasn't in the cache