Cache provider improvements

* PHPdoc comments are added
* LocalMemory provider is patched to clone objects in Get/Set operations to prevent same object sharing and modifying.
* QMultiLevelCacheProvider is patched to work properly.
* CreateKey function is adopted to work with older php versions
Merge branch 'master' of github.com:olegabr/framework into feature-CacheProviderImprovement
Merge branch 'master' of github.com:olegabr/framework into feature-CacheProviderImprovement
Merge pull request #267 from olegabr/feature-CacheProviderImprovement

Problems with cache providers are solved