files: Avoid crash if `fileinfo` extension missing
forms: Properly export choices lists

Previously, this was not ported properly now that multiple selections are
supported in the choice field and derivatives.
Update tickets.inc.php
bug: Check to make sure $ost is initialized
Merge pull request #1456 from protich/issue/1455

bug: Check to make sure $ost is initialized

Reviewed-By: Jared Hancock <jared@osticket.com>
thread: Fix regex for ticket # in email subject

The ticket number regex was changed with the advent of custom ticket
numbers, and it matches the closing punctuation in [#12345], that is, the
closing bracket would be included in the ticket number sought in the
database. Therefore, it would never match the ticket number properly.

The new regex attempts to match punctuation and non-punctuation groups so
that punctuation in the middle of the ticket number is matched; however,
punctuation at the end is not. So #12345+DEPT will match properly and will
ignore any trailing whitespace and punctuation.
i18n: Clarify attachment settings labels
forms: Drop custom data when removing a user
Merge pull request #1492 from greezybacon/issue/user-del-dyn-data

forms: Drop custom data when removing a user

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #1486 from greezybacon/issue/subject-tix-number

thread: Fix regex for ticket # in email subject

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #1441 from Chefkeks/patch-7

i18n: Add a few forgotten strings #2

Reviewed-By: Peter Rotich <peter@osticket.com>
Disable auto-responses on staff created tickets

Take into consideration the auto-response settings when sending out new
ticket by staff notice to the end user.
pdf: Fix invalid UTF-8 characters error message
Merge pull request #1512 from greezybacon/issue/pdf-invalid-utf

pdf: Fix invalid UTF-8 characters error message

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #1489 from greezybacon/issue/more-phrases

i18n: Clarify attachment settings labels

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #1509 from protich/issue/disable-auto-response

Disable auto-responses on staff created tickets

Reviewed-By: Jared Hancock <jared@osticket.com>
Merge pull request #1437 from greezybacon/issue/1427

files: Avoid crash if `file info` extension missing

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #1436 from greezybacon/issue/choices-export

forms: Properly export choices lists

Reviewed-By: Peter Rotich <peter@osticket.com>