MDL-47572 libraries: modify unittest to avoid random timing fail

Thanks to Nigel Cunningham
MDL-47583 tinymce_managefiles: correctly decode filename
MDL-47583 atto_managefiles: correctly decode filename
MDL-47575 gradebook: Show weights and contribution by default.
Merge branch 'MDL-47575-master' of git://github.com/zbdd/moodle
Merge branch 'wip-MDL-47583-master' of git://github.com/marinaglancy/moodle
Merge branch 'wip-MDL-47572-master' of git://github.com/marinaglancy/moodle