Use page break line as the delimiter of some text

Emacs has [Page](http://www.gnu.org/software/emacs/manual/html_node/emacs/Pages.html) feature. It is useful to divide some text. If you feel that page break line (`^L`) is ugly, use [page-break-ilnes](https://github.com/purcell/page-break-lines), which is a nice package.