1. Add a column to the course_sections table

ALTER TABLE  `mdl_course_sections` ADD  `displayname` VARCHAR( 30 ) NOT NULL COMMENT  'used to display a "friendly" topic name'

2. Patch $libroot/navigationlib.php, $wwwroot/course/editsection.php and $wwwroot/course/editsection_form.php

navigationlib.php:
Changed to use the new "displayname" field on the $section as the label if it is set

editsection.php & editsection_form.php:
Modified to implement a "Display Name" field to allow user to change the displayed label.