- made placeholders visible for apache, too
- added event raise at formdef loading (on_before_formdef and on_after_formdef)
- added possibility to put plugin files into module/lib/plugin.d/ directory

- fixed letsencrypt domain list

- added cron for letsencrypt renewal

fixed error in mail_backup -> all mail-backups would have been deleted with old code because of * in filename

Conflicts:
	interface/lib/classes/remoting.inc.php
	interface/web/mail/templates/mail_user_backup_list.htm
	interface/web/sites/lib/lang/en_web_backup_list.lng
	interface/web/sites/lib/lang/es_web_backup_list.lng
	interface/web/sites/lib/lang/tr_web_backup_list.lng
	server/plugins-available/backup_plugin.inc.php

Replace fastcgi_pass unix:/var/run/php5-fpm.sock; with fastcgi_pass unix:{fpm_socket}; in phpmyadmin and squirrelmail blocks, as they are considered apps and should use the same (apps.sock) listener.

Adding SSLStaplingCache shmcb:/var/run/ocsp(128000) to vhost template conf if apache version >= 2.4 and ssl enabled

Fix by dirkd: Since file() doesn't remove "\n" from the lines read the condition $lines[$l] == '' never evaluated to true. So $mailHeaders would always contain every line from the template while $mailBody contained none of them.

Together with the bugfix of PHP#68776 [1] disallowing multiple "\n"'s & preceding "\n" in mail()'s $additionalHeaders arg this caused mails not being sent because $mailHeaders would include at least one "\n\n" which was meant to separate the mail headers from the body.

[1] https://bugs.php.net/bug.php?id=68776

Since file() doesn't remove "\n" from the lines read the condition
`$lines[$l] == ''` never evaluated to true.
So $mailHeaders would always contain every line from the template while
$mailBody contained none of them.

Together with the bugfix of PHP#68776 [1] disallowing multiple "\n"'s &
preceding "\n" in mail()'s $additionalHeaders arg this caused mails not
being sent because $mailHeaders would include at least one "\n\n" which
was meant to separate the mail headers from the body.

[1] https://bugs.php.net/bug.php?id=68776