block_istart_reports: Now checks istart dates before sending report.
block_istart_reports: Now uses calculated course id throughout.
block_istart_reports: Now uses user profile field to obtain managers email address.
block_istart_reports: Now saves queue of reports for given course, group, user and date in the DB table block_istart_reports_queue.
block_istart_reports: Now cleans old queued reports from the database.