MySQL is kind enough to quietly truncate the filedata field when attempting
to CONCAT data beyond the size of max_allowed_packet. The simplest fix is to
automatically adjust the max_allowed_packet to the size of the file being
uploaded plus some extra. See MySQL bugs #22853, #34782, and #63919 for more
discussion on the issue.

The max_allowed_packet variable default to 1M, but is expandable to 1G.
Therefore, the fixed limit of attachments for osTicket will be 1G, since it
would be impossible for MySQL to append data after that mark. *Sigh*

MySQL has a limit on the maximum amount that can be transferred in one
statement. It's the max_allowed_packet setting. The value of this setting
will be the approximate upper limit of attachments that can be handled by
the database given the current access model for osTicket.

The issue came up for attachment uploads and was corrected, so that uploads
are chunk inserted into the database. Downloads, however, were forgotten.
Strangely, it took quite a bit of debugging to track down the problem.

This patch corrects attachment downloads by fetching 256kB chunks of the
attachment at a time and sending them directly to the client. This will also
overcome PHP's memory limit which would be the second-level blocker of
attachment sizes. Lastly, the AttachmentFile::getData() method is simulated
using output buffering. This will provide the same access as the previous
getData() method; however, it is still subject ot PHP's memory limits.

Add Content-Type

Reviewed-By: Peter Rotich <peter@osticket.com>

Implement automatic client logins

Reviewed-By: Peter Rotich <peter@osticket.com>

Feature/nested help topics

Reviewed-by: Jared Hancock <jared@osticket.com>

Rename 'Knowledgebase' to FAQs and Categories to FAQ Categories

Reviewed-By: Peter Rotich <peter@osticket.com>

open_basedir restriction while adding staff

Reviewed-By: Peter Rotich <peter@rotich.com>

When reading data from /dev/urandom and friends on *nix systems with the
open_basedir setting enforced.

Fix team selection and cancel navigation for staff page

Reviewed-by: Jared Hancock <jared@osticket.com>

Remove forced password change on upgrade

Reviewed-by: Jared Hancock <jared@osticket.com>

This will help distinguish between the knowledgebase part which encompasses
FAQ's and canned responses, and the FAQ part which contains the articles
detailing frequently-asked-questions.

* Auto rehash MD5 based passwords

Remove short_open_tags dependency

Reviewed-by: Jared Hancock <jared@osticket.com>

Fix filters applied on web created tickets

Reviewed-by: Jared Hancock <jared@osticket.com>

Check access post-update

Reviewed-by: Jared Hancock <jared@osticket.com>

Force password to change when changing password

Reviewed-by: Jared Hancock <jared@osticket.com>

Fix staff and departments count on groups page

Reviewed-by: Jared Hancock <jared@osticket.com>

Fix Quoted Reply not removed

Reviewed-by: Jared Hancock <jared@osticket.com>