This will remove the upper limit of BLOB sizes imposed by MySQL with the
max_allowed_packet setting completely.

This adds a new table %file_chunk which will contain the filedata in smaller
chunks (256kB). It also includes a new class, AttachmentChunkedData, which
will handle reading and writing the data, abstracting away the chunks.

This is done by migrating data from the %file table to the %file_chunk
table. One must beware that this must safely (the migration that is) plug
into the both the live osTicket developers as well as the users doing a full
upgrade from osTicket-1.6*. For this, the AttachmentFile::save method was
patched to use the new AttachmentChunkedData class to write the attachment
data to the database in chunks. That is, the migrater will use the new code
on the major upgrade and bypass the filedata column of the %file table
altogether. Therefore, the patch associated with this commit will not
migrate any data for the major upgrade.

For developers doing incremental upgrades, the patch included in this
commit will transfer the data from the %file data to the new %file_chunk
table by chunking it. As written, only the first 16MB of the attachment is
migrated. This could easily be adjusted, but it seems like a reasonable
limit for now.

Fix missed table name change - a bug on new installations

Reviewed-By: Peter Rotich <peter@osticket.com> [self reviewed dev hot fix]

Feature/filters revisited

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

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.

Force target selection on filter form
Add minor code improvements

Installer error reporting setting.

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

Add auto-focus to username field

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

Admin Panel Revisited.

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

Encode text to UTF8 on PDF exporter

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

Protect Include directory

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

Add GROUP BY clause to canned response load

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

Change the with of the info table

* Change table name from ost_email_filter* to ost_filter*
* Add patch for target field.

* Collapse date settings into system settings.
* Move auto-cron setting to emails settings page.
* Move clickable urls setting to tickets settings page.

 * Collapse Department into Staff tab.
 * Add a new 'Manage' tab - home for managing items, lists..etc.
 * Collapse Help Topics into Manage tab.
 * Move SLA and API from Settings to Manage tab.

Add Content-Type

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