If a staff member creates a new ticket and cancels the user-lookup /
create-new-user dialog, and the contact information form has a required field
other than the name and email address fields, the ticket cannot be created
because the required fields for new clients are not shown and can therefore
not have a required value.

This patch allows new clients to be created without the required fields when
the ticket is created by staff members.

Careful transcoding attachments with a charset

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

tnef: Strip null bytes from attachment filenames

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

If a non-text attachment specifies a charset in the content-type header,
don't transcode the content before saving it to the database. This can
corrupt attachments which have a header like the following:

Content-Type: application/pdf; charset=UTF-8

Since a PDF contains binary data, coercing it to UTF-8 encoding will drop
characters not valid in UTF-8 and will corrupt the attachment data.

Also support the TransportName in the properties list and prefer it over the
attachment-level attribute, as it is Unicode encoded.

filter: Implement priority 

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

The priority setting was broken when priority was added to the dynamic data

Register session close on shutdown at the start of session handling

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

pipe: Honor attachment ext and size restrictions

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

smtp: Reuse existing connections where possible

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

tnef: Support TNEF for fetched emails

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

This is necessary to make sure session data is saved on redirect.

Previously, the data blocks were inspected byte for byte. Now data blocks
are parsed 1k at a time. Fewer PHP function calls ultimately means faster
performance.

Parse Microsoft TNEF email attachments

Peter Rotich <peter@osticket.com>

Shift error checking into Mail_Parse::parseAddressList

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

This should speed up the system where several emails and alerts will be sent
through the same SMTP account in the same request.

Simplify workflow for new ticket by staff

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

forms: Allow searching any priority

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

If the system has only one help topic automatically select the help topic
and display any associated custom form.

Priority field and custom list fields have a prompt value (shows up only for
drop-down widget). And the short and long answer fields have a placeholder
configuration item.

Ignore case for ticket variables on custom fields

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

Search for system emails in To and Delivered-To

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

This is needed to help us remove invalid characters set by some mail
clients.

Previously, the Delivered-To header was only used if the To header was not
found

i18n: Much better compat imll of mb_* funcs

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