Hi Valery

I have tried to clean up the mail notification part of the code. Mail sending and template parameter processing are now extracted into two library functions, scheduler_get_mail_variables() and send_email_from_template().

Improvements include:

• Appointment reminders are now handled by mail template scheme as well, and can be sent in plain text or HTML.
• de_utf8 translations for mail templates added.
• Fixes a bug with cancellation notifications for volatile slots (for all I can see).
• Resolves two other open issues, CONTRIB-1151 and CONTRIB-1289.
• Student/teacher names are now hyperlinked in HTML mails.
• Should make customization and maintenance of mail notifications easier.

es_utf8 mails are still untranslated.

It's a rather large patch (sorry). Everything is done for the MOODLE_19_STABLE branch, some modifications for Moodle 2.0 might be needed. The diff is attached. There are some new files (i.e. extra mail templates); I will attach these as a ZIP file separately.

Henning