init cache manager & event listener
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration
refactored http cache manager
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration
updated symfony http-cache manager
added fos http-cache dependency
added symfony proxy client (cache manager)
added kernel.environment for http-cache event-listener
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration

Conflicts:
	composer.json
	src/Sulu/Component/Webspace/Manager/WebspaceManager.php
Merge branch 'develop' of git://github.com/sulu-cmf/sulu into feature/cache-expiration

Conflicts:
	composer.json
	src/Sulu/Component/Webspace/Manager/WebspaceManager.php
Merge branch 'feature/cache-expiration' of git://github.com/sulu-cmf/sulu into feature/cache-expiration

Conflicts:
	composer.json
	src/Sulu/Component/Webspace/Manager/WebspaceManager.php
Merge pull request #105 from sulu-cmf/feature/cache-expiration

[FEATURE] basic cache expiration