* Added `cache_listeners` option, which takes an array of `CacheListener`s, who get notified and can optionally act on a Response based on a cache hit or miss event. An implementation, `AddHeaderCacheListener`, is provided which will add an `X-Cache` header to the response with this information.
* Removed check if etag is a string. Etag can never be a string, it is always an array.
## 1.4.0 - 2017-04-05
### Added
-`CacheKeyGenerator` interface that allow you to configure how the PSR-6 cache key is created. There are two implementations
of this interface: `SimpleGenerator` (default) and `HeaderCacheKeyGenerator`.
### Fixed
- Issue where deprecation warning always was triggered. Not it is just triggered if `respect_cache_headers` is used.
## 1.3.0 - 2017-03-28
### Added
- New `methods` option which allows to configure the request methods which can be cached.
- New `respect_response_cache_directives` option to define specific cache directives to respect when handling responses.
- Introduced `CachePlugin::clientCache` and `CachePlugin::serverCache` factory methods to easily setup the plugin with
the correct config settigns for each usecase.
### Changed
- The `no-cache` directive is now respected by the plugin and will not cache the response. If you need the previous behaviour, configure `respect_response_cache_directives`.
- We always rewind the stream after loading response from cache.
### Deprecated
- The `respect_cache_headers` option is deprecated and will be removed in 2.0. This option is replaced by the new `respect_response_cache_directives` option.
If you had set `respect_cache_headers` to `false`, set the directives to `[]` to ignore all directives.
## 1.2.0 - 2016-08-16
### Changed
- The default value for `default_ttl` is changed from `null` to `0`.
### Fixed
- Issue when you use `respect_cache_headers=>false` in combination with `default_ttl=>null`.
- We allow `cache_lifetime` to be set to `null`.
## 1.1.0 - 2016-08-04
### Added
- Support for cache validation with ETag and Last-Modified headers. (Enabled automatically when the server sends the relevant headers.)
-`hash_algo` config option used for cache key generation (defaults to **sha1**).
### Changed
- Default hash algo used for cache generation (from **md5** to **sha1**).
### Fixed
- Cast max age header to integer in order to get valid expiration value.
