This implements rendering mime-types with content-type 'text/markdown'
and 'text/x-markdown' into HTML in the preview and show views (if not
"dispositioned" as "attachment"), but not in the get view for attached
files (the one opening attachments in an external window.)
* Check if "inline" msg part is actually referred to
If there's no reference to it in a sibling HTML part then we handle it
as a classic attachment (which is shown as downloadable).
* Fetch all msg headers also for images to always get Content-Location
Previously all headers were only fetched for message/rfc822, or
if the Content-Type's "name" parameter was set, or if a Content-ID was
set.
The RFC doesn't require neither the "name" parameter nor a Content-ID
for using Content-Location, though, so we shouldn't depend on those.
Instead now all headers are also fetched if the main part of the
Content-Type is "image", to catch more cases.
* Parse HTML for references only on demand
* Typos and comment formatting
* Don't skip test anymore
We want it tested!
* More MR tests with images
* Remove early special handling for "inline" images
We decide later, which attachment is considered "inline" and which
isn't.
* Remove early resolving of references in TNEF parts
* Testing message rendering of TNEF emails
* Don't use image disposition, it's unreliable
* Split adding raw parts and attachments
* Fix renaming variable
* Rename file to make its test be run
* Remove outdated script
* Annotate test cases with GitHub issue numbers
* Fix test case class name
* remove comment
* Test inline image message rendering
* Rename test file to reflect cases better
* Reduce image used in test email
It doesn't change much, but there's also no sense in decoding big images
that we don't use.
* Remove unused variable initialisation
* Fix displaying message/rfc822 parts
The previous code contained a simple error that assigned the body part
to the $headers variable (which then couldn't be parsed and got
discarded).
* Test rendering of attached message/rfc822 parts
