Author: Michael Hawkins
MDL-72629 timeline: Reduce footprint when a course has no events
This also improves the noevents string so it makes sense in all
contexts.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=34d6916968c12fcc96447bae04b8dba3d8b26437
http://github.com/moodle/moodle/commit/34d6916968c12fcc96447bae04b8dba3d8b26437
+ 4.0 en [noevents,block_timeline]