Merge branch 'hotfix-487'
Fix 489 Invalid signature error when installed on subdirectory
Fix #490 denied access to admin/department page

When there is no department in database, accessing admin/department with
root account will get permission denied. This is impossible to create
departments with new instance.
Fix #491 Adding class member failed when duplicate username in request

When adding users to a course with API, if there is a duplication in the
request body, e.g., same username with different case (for some reason,
Blackboard allows it), the operation fails.
changed student's usernames to redshirt00XX instead of student no
changed tests to use new usernames (eg. redshirt0003)
Fix the fixtures and tests for changing the usernames
Merge branch 'hotfix' into dev

Conflicts:
	app/controllers/departments_controller.php
	app/tests/cases/controllers/v1_controller.test.php

Basically took all the hotfix changes.