"Mail conversation Update" for Zeuner 3

* Additional filters: | if conversation has only one mail (and unique in database and no more than 1 mail for other conversation with same mail) | by customer email address | by customer email domain | by booking address (see multi-domain feature below) * New reminders for you/your staff: | if agency doesn't respond to initial request within x days * Wrong code replacement: | replace redirect codes with the correct one for customer/agency also | outside of the subject line | possibility to view and change the redirects in the admin section in | order to repair broken redirects * New customer communication: | send confirmation mail when booking form is submitted (try to track | if customer opens it) | send reminder notice when customer doesn't respond to first | agency reply within x days | send info to agency if mail was verify * Mail template engine in admin backend: | edit mail texts for automated mails in admin backend * Analysis tool in admin backend: | visual status display in conversations view (to see if customer | doesn't respond / doesn't open tracking mail) * Export function: | CSV output of lists for use with Excel * multi-domain function: | allow to run multiple booking addresses/domains on one database | allow filter by booking address for investigating customer delivery | differences (see filters above) * performance optimization: | analyze what makes the conversations list run slowly, and optimize it * improved robustness: | when database server goes down, hold messages until it comes back | up so there is no issue with missing redirects * DKIM integration: | sign mails using DKIM for avoiding spam flagging (only recommended | after setting up your DNS for this!) * conversation data from new forms in admin section | dump unrecognized data fields with their internal name in admin section