Change mobile breakpoint

- [new] Tablet breakpoint kicks in at 9 columns
- [new] Intermediary states for headline text size and column space between mobile landscape and right column breakpoints
- [refactor] `article-v2…` classes are deprecated and renamed into `article…`

![ ](http://s2.developerslife.ru/public/images/gifs/7a221001-96ed-41f0-8088-3227fcdae925.gif)