Provide a SwiftMailer transport that only saves send mails to files
We introduced the SwiftMailer interface in t3lib_mail in 4.5 alpha2. So we can now generate RFC conformant mails and have a powerful mail engine available which also supports different transport mechanisms (like mail(), sendmail and direct SMTP).
To ease debugging mail sending in a TYPO3 installation, it might be useful for a complete installation not really send mails, but just save them to a file.
This RFC provides this feature, allowing the admin to configure the new transport "mbox", which saves all mails to a mbox-conformant file (simple text file, see RFC 4155). This file can be viewed with a regular text editor or a mail client which can open a "mbox" file.
Along with Jigal's RFC #24222 which hooks into all other mail() usage we are now able to log every outgoing mail to a file!
This feature is a follow-up the the new mailing API and will be included according to the rules for "new features" in this phase (see http://forge.typo3.org/projects/typo3v45-projects/wiki/Feature_Freeze, where "t3lib_mail" is listed as potential candidates for follow-ups).
(issue imported from #M16610)