Application lifecycle conflicts on exception handling

@pylover in #126, you mean when `_handle_exception` hook called, no hook should call after that. but by referring in our code: 
https://github.com/Carrene/nanohttp/blob/7c536c1667c3151453c34cb7e84a12e509995144/nanohttp/application.py#L47-L74 we called `end_response` in wrong place and should remove it. @pylover right?