Add 10-percent heuristic to httpCache.isStale()
Re-arrange flow control of isStale, modify tests to add a resource that is fresh by 10% heuristic but stale by cache control.
mo tests, mo problems
pew pew
Merge pull request #207 from mobify/v1.1-jazzcat-10-percent-caching

Add 10-percent heuristic to httpCache.isStale()