Git commits in Moodle 2.8.x by Wesley Situ

commit 0c8e82aade1a33bba73261651aa44509699d0394
Author: Wesley Situ <wsitu@oid.ucla.edu>
Date:   Wed, 21 Jan 2015 03:27:36 +0800
Tag:    v2.8.3

MDL-48916 atto_undo: Clarify text for "Undo/Redo"