Adds an extra import section alongside the existing export in the
calendar views. Allows the user to import from either a file or a
URL as a subscription, with an optional polling interval of hourly,
daily, weekly, monthly, or annually. This subscription may be added
to the user, group, global or course calendars. These subscriptions
are tracked in a separate database table, and an extra column added
to the events table to relate them to the subscription. The event
uuid field is also expanded to allow for the RFC-2445 UID property.
Subscriptions are listed on the calendar view page, and can be
added and removed, manually polled, and the polling interval
adjusted. Subscription events are updated on cron.
Rather than overloading the $CFG->bloglevel setting which had a
confusing UI in the appearance subsystem.
In order to achieve this we modify take the defaults from the existing
bloglevel setting and set that for $CFG->enableblogs. Note that in order
to prevent a bad default settings from being set we also set
$CFG->bloglevel to a valid 'enabled' setting.
The oldquestiontextformat was used during previous upgrade and is not necessary any more.
Next time we should add these temporary upgrade columns to install.xml files.
This fixes WCAG 2.0 compliance because we were already using HTML5 markup.
The strict XML headers setting never worked for production servers, developers
used browser validators for compliance testing. XHTML 5 option is relatively
similar to this obsolete option, but still it can not be used on production servers.
XHTML Strict 1.x was a standardised dead end, HTML5 is the new de-facto-standard
supported by all major browsers including latest versions of IE.
Please note nothing changes in our coding style because HTML5 is a superset of
several previous standards, it is recommended to use only features that are
already implemented in all our supported browsers.
