Fixes the rewriting of the `key` field in the ticket thread body. The
storage de-duplication system may replace the `key` value with an existing
one. The ticket thread system will use the `key` value assigned when the
file is committed to the database or the existing key of the duplicate file.

Also fixup installation issues with the attachment storage plugin
architecture

  * Include a `bk` column to store the storage backend
  * Include a `signature` column which represents a repeatable hash of the
    file contents
  * Rename `hash` to `key` since it isn't a real hash

The concept of extid is being retired to pave-way for customizatable ticket
numbers.

 - This is necessary so we'll have a name on record - even on user deletion.

Pass the user id (uid) to ticket create instead of unpacked data.

Using email headers try to determine the user.

With the introduction of collaborators, this is necessary so we can determine who is replying without relying on the
FROM address - which can be easily spoofed.

Conflicts:

	include/upgrader/streams/core.sig

We introduced a glitch in 29b37144, which was the patch that introduced
matching on email headers other than the Subject.

I misinterpreted the original `preg_match()` regex, thinking that it was
requiring brackets. Looking at it again today, I see that it didn't. The
current one does, however, require surrounding brackets.

This patch also allows for extra letters or dashes between the `#` and the
ticket number. Eventually we should allow the ticket number itself to have
extra characters -- be formattable.

Fixes osTicket/osTicket-1.8#342

And avoid double encoding email bodies if html thread is not enabled

Previously, the References header emitted by the system for new thread
entry auto-responses and alerts included the message-id for which the email
was a reply in the `References` header. This patch corrects the issue by
placing the reply message-id in the In-Reply-To header, and constructs a
correct References header.

That is, if available, the References header received in the email that was
used to create the thread entry is appended to the message-id the email is
actually in reply to. This is the expected usage of the References header.

Use a PHP setup which uses the built-in PHP tokenizer to parse and traverse
PHP scripts to determine (possible) access to uninitialized variables

* %{ticket.thread.original} represents the original message submitted when
    creating the ticket
* %{ticket.thread.lastmessage} represents the most recent message submitted
    by the end user

Process inline attachments in thread entry and support inline images in
piped emails

Support inline images across the system, with draft support

Migrate to a single attachment table
    That way we don't need a new table for everything we need to attach an
    inline image to (like a signature, for instance)

Add richtext support for internal notes

Implement images on site pages

* Image paste in Redactor
* Make non-local images optional
* Placeholder for non-local images
* Fix local image download hover
* Don't re-attach inline images

line is used.

id/number.

* Ticket number will be customization in the future
* Ticket thread only link to Ticket should be internal ticket id.

if the References or In-Reply-To header matches in a way that continues a
ticket's thread, include the attachments in the thread if allowed by the
system settings.

In the event that the system is set to do-nothing for POP fetched
emails, and eventually, one of the emails is rejected, ensure that the
message-id is logged so that the message will not be re-fetched, even if it
is undeleted.

When comparing the From address of incoming email. If the ticket owner sent
an email back into the system and the email address did not match exactly,
case-wise, the email would not be considered from the ticket owner.

If an alert message manages to loop back into the ticketing system, refuse
posting to the ticket thread. Technically, the message should be marked as
an auto-response message; however, auto-response messages should usually be
allowed to be appended to the ticket thread.

This patch will check if the From email header cites an email address that
is a system email address (visible in the Emails section of the Admin
Panel). If it is, the email is completely ignored.

This patch affords an administrator the ability to remove the
[#%{ticket.number}] from the email template subject line for the new ticket
autoresponse and the new message autoresponse. Previously, the ticket number
with a prefixed hash in brackets was used to identify which ticket thread an
email was in reference to.

With this patch, the email message-id (which was already kept on file) is
sent in the MIME "References" header. When a user responds to and
autoresponse email, the "References" will include this message-id in the
return email. The ticket thread is then matched up with the email based on
the message-id rather than the subject line.

Ticket numbers are still supported in the subject line, in the event that
non-compliant email clients do not properly include the References header.

Fully implement thread entry class and types (Note, Message & Response)