Minz: remove one layer of ob_ (experimental)

https://github.com/marienfressinaud/FreshRSS/issues/303#issuecomment-38351311
https://github.com/marienfressinaud/FreshRSS/issues/163
* Remove Minz_Response (not needed anymore)
* Move Minz_Request::reseted to Minz_Dispatcher::reset()