Git commits in Moodle x.x.x by Juan Pablo de Castro

commit 6aa8a3b6d00fa42f49c92cc520d9de93bd0f7242
Author: Juan Pablo de Castro <jpdecastro@tel.uva.es>
Date:   Fri, 09 Feb 2018 02:57:35 +0800
Tag:    v3.6.0-beta

MDL-14274 lib/evalmath: support of conditional math in formulas.