The issue #195 is fixed

* Constants `__FILE_FORM_STATE_HANDLER_GARBAGE_COLLECT_INTERVAL__` and `__FILE_FORM_STATE_HANDLER_GARBAGE_COLLECT_DAYS_OLD__` are added
* Example for the QMultiLevelCacheProvider options usage is provided.
Merge branch 'bug-195' of github.com:olegabr/framework into norma-soft