2.0.0-alpha1

General

• Updated the version of FOSHttpCache to 2.0.0. See the FOSHttpCache changelog
  for more information. Most importantly, we removed the hard coupling on the
  Guzzle HTTP client (using HTTPlug). Your composer.json now needs to
  specify which HTTP client to install; see the installation instructions.
• Deprecated methods have been removed.

Proxy client

• The configuration for the proxy client has been adjusted. Proxy servers are
  now configured under http and servers must be a list - a comma separated
  string of server IPs is no longer supported.

Event listeners

• BC break: the UserContextListener constructor signature was changed to
  take an array of options.
• BC break: renamed the event listener classes to XyzListener.

Rule matcher

• BC break: The match_response and additional_cacheable_status
  configuration parameters were removed for individual match rules.

• BC break: The second argument of the RuleMatcher constructor was changed
  to take a ResponseMatcherInterface.

• Cacheable status codes are now configured globally
  (cacheable.response.additional_status or cacheable.response.expression).

Tags

• BC break: The TagHandler has been split. Invalidating tags happens through the
  CacheManager (if you use annotations for tag invalidation, you don't need to
  change anything). Recording tags and writing them into the responses is now
  done through the SymfonyResponseTagger.

Tests

• BC break: Dropped the proxy client services as they where not used anywhere. The
  services fos_http_cache.test.client.varnish and
  fos_http_cache.test.client.nginx no longer exist.

User context

• Added an option always_vary_on_context_hash to make it possible to disable
  automatically setting the vary headers for the user hash.