Author: Frédéric Massart
MDL-56016 theme_boost: Add plain preset for plain Moodle & Bootstrap
http://git.moodle.org/gw?p=moodle.git;a=commit;h=239fd05cc9afc169fc8da2ec2e3f9de6514210b8
http://github.com/moodle/moodle/commit/239fd05cc9afc169fc8da2ec2e3f9de6514210b8
+ 3.2 en [presetplain,theme_boost]