This patch replaces all homegrown timezone
stuff with standard PHP date/time code.
The main change is the introduction of core_date
class that returns normalised user and server
timezones. From now on nobody should be using
$CFG->timezone or $user->timezone directly!
Other new features and fixes:
* admins are prompted for timezone during install
* editing of other users is finally fixed
* timezones are displayed in user profile
* new $this->setTimezone() in phpunit
* time locale is now automatically reset in phpunit
* timezone is now automatically reset in phpunit
* phpunit has Australia/Perth as default timezone
This reduces the period of time that some of the unit tests
for calculate_next_automated_backup() are failing right now
(from 1week to just some hours around the DST changes).
Note it's not the final solution because they will still fail
when New_York or Brussels DST changes are about to happen, but
to get this completely fixed we'll need to wait to switch from
current custom TZ/DST support to PHP built-in one.
Andrew Hancox