[mms] Allow drag & drop/pasting of images into the HTML editor.
Fix deleting attachments from dynamic view
Fix PHP issue causing only the first attachment's data to be inserted into the message

Nothing like spending hours trying to track down the issue, only to find
out it may be an issue in PHP's core.  See:

https://bugs.php.net/bug.php?id=64146
Don't show attachment info for related data