Place the message-id in the body of the email

This approach will help detect responses to the ticket thread from mail
clients which do not include the References and In-Reply-To MIME headers.
This also allows the Subject line to continue to omit the ticket number.
oops: Don't crash on setting Return-Path
file: Use the database to save files as a failsafe
file: Fix saving backend char

Because the file type normally defaults to the system default (for fetched
emails at least), the backend char was not saved, because the file type char
was left at the system default. Therefore, if a file is saved to a backend
other than the default (in the database), the data will likely be saved to
the backend, but the file metadata will reflect the incorrect backend.

The only reason the file type char was not defaulted in the
AttachmentFile::save() method was for the migration process from osTicet 1.6
to osTicket 1.7. This is mitigated by passing `false` specifically from the
migration task.

Since otherwise the file type char is now set, the backend char is now saved
with the file metadata.
Only add emailed collaborators if we have a positive match on delivered to
email.

This is necessary to eliminate possible loop when an email is sent to a
virtual/aliased address. Not all mail servers add delivered-to header!
Expose staff's signature as possible variable in collaborator's template
forms: Export textual name for custom list fields
forms: Require 'name' for custom lists
Merge pull request #604 from protich/feature/collaborators+aliases

Only add emailed collaborators if we have a positive match

Reviewed-By: Jared Hancock <jared@osticket.com>
Merge pull request #605 from protich/issue/collabs-notice-signature

Expose staff's signature as a variable in collaborator's template

Reviewed-By: Jared Hancock <jared@osticket.com>
oops: Fix display of forgot-my-password link

Reported by @ntozier
Use up-to-date user/staff name instead of poster when displaying ticket thread

Join to staff/user tables to get current name when fetching thread entries.
Merge pull request #608 from protich/feature/poster-name

Use up-to-date user/staff name instead of poster when displaying ticket thread

Reviewed-By: Jared Hancock <jared@osticket.com>
Use the company name for the copyright.
Preserve inline image floating in ticket thread
Merge pull request #586 from protich/feature/copyright

Use the company name on the copyright notice.

Reviewed-By: Jared Hancock <jared@osticket.com>
Merge pull request #611 from greezybacon/issue/forgot-my-password

oops: Fix display of forgot-my-password link

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #610 from greezybacon/issue/list-field-export

Fix export of custom list fields

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #595 from greezybacon/issue/bk-char

file: Fix saving backend char

Reviewed-By: Peter Rotich <peter@osticket.com>
lint: Fix syntax error regression