Main, Main::PSGI: Remove to_app() method from BusyBird::Main. That required Main.pm to load Main::PSGI, which loads Main::PSGI::View and tons of other modules for rendering. Main::PSGI::create_psgi_app() is now an automatically exported function, which does the same thing as the removed to_app() method.
t/Main_PSGI_View.t: write tests about template_functions().
Main::PSGI::View: implement template_functions().
Main::PSGI::View: partially implement template_functions_for_timeline() functions. status.tt is revised to use the template functions. Tests needed.