dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
* Form to control the perpage variable for the upgradable assignments table.
* Set timeout and increase memory limit for batch upgrades
* Output/renderer pages to the upgrade progress is progressively displayed
* Cleanup of relative includes in assignmentupgrade tool
* More verbose errors reported for failed upgrades
