Variable movement and related changes.

Font related variable movements.
Also added missing variables to customizer and fixed inconsistent data between variables.less and customize.html.

@mdo & @cvrebert please have a look and let me know if got errors.

Note: I tested locally and did grunt with success.

Sorry about length of pull request, I wish I could send it in small pull requests but I can't (because of my current work load). So I spent full day on this so we can quickly move onto Final Release.