Added support for simple cache (#134)

* Added support for SimpleCache

* Added tests

* Bugfix with cloning

* Style fix

* Minor

* Updated integration tests version

* Bugfix

* Allow same keys

* cs

Author: Nyholm

composer.json

@@ -36,7 +36,7 @@
     },
     "require-dev": {
         "phpunit/phpunit":         "^4.0 || ^5.1",
-        "cache/integration-tests": "^0.14",
+        "cache/integration-tests": "^0.16",
         "cache/array-adapter":     "^0.5"
     },
     "autoload":    {