Add tests for expired items without must-revalidate.
Merge pull request #20 from deviantintegral/must-revalidate-test

Add tests for expired items without must-revalidate.
PR #21: Add support for including Vary headers in cache keys.
Merge pull request #21 from deviantintegral/vary-support

Support Vary response headers in cache keys
Issue #22: Add a test for the can_cache option.
Merge pull request #23 from deviantintegral/can-cache-test

Issue #22: Add a test for the can_cache option.
Fix not adding timezone to dates.
Merge pull request #24 from deviantintegral/missing-date-gmt

Fix not adding timezone to dates.
Issue #22: Add $defaultTtl to CacheStorage constructor.
Merge pull request #25 from deviantintegral/cache-set-ttl

Issue #22: Add setDefaultTtl() to CacheStorage.
Fix stale-if-header not being added to max-age.
Merge pull request #27 from deviantintegral/stale-if-header-ttl

Fix stale-if-header not being added to max-age.
fix error caches responses for without vary headers
Use date() method to fix missing GMT.
Merge pull request #29 from deviantintegral/can-cache-date

Use date() method to fix missing GMT.
Merge pull request #26 from sergey-k/master

Fix error caches responses for without vary headers
Fix max-age and freshness confusing zero and null.
Adds tests for stale-if-error behaviour.

This also fixes:
 * Adding duplicate headers on stale responses that are handled in
   onComplete.
 * Overwriting an event variable with an exception.
 * can_cache test assuming can_cache works in error conditions.
Bumped branch alias to 0.2
Merge pull request #31 from GrahamCampbell/patch-1

Bumped branch alias to 0.2