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.

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

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.

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

If a wrapped mail is sent, copy the Delivered-To header into the nested
message so it will be clear(er) how the mail arrived into the system. Also,
copy the Message-Id into the nested mail if there is none to help against
mails delivered repeatedly.

Some emails providers (e.g gmail/google) won't deliver emails marked
bulk/autoreply to group email address.

Until we add text/plain bodies to the ticket thread without an enclosing
<pre> element, we should not treat the <pre> element like a code or
blockquote block.

On some combinations of operating systems, PHP and libpcre versions, `\s`
will match the iso-8859-x non-breaking-space, 0xa0. This regular expression
will munge the UTF8 encoded version, 0xc2a0 to 0xc220, which is not a valid
UTF8 character.

When inserted into a UTF8 field in mysql, the text will be truncated at and
after the first invalid character.

These functions don't appear to be used an could corrupt UTF-8 encoded text

Fixes a few E_NOTICE messages
Drops bounce checking inside autoReply checking

If MySQL error #1213 (deadlock found when trying to get lock) is returned
from query, it is safe to retry the query.

This patch will retry queries up to two times for a total of three. If the
query cannot be executed without error #1213 after the third time, the error
is logged as usual, and the system continues with the failed query.

Rename routines to make it a little clear on what they do

This patch addresses an issue where a client may have upper-case letters in
their email address. When visiting the client portal to check the ticket
status, previously, the exact same case would be required in the 'Email
Address' box.

This patch removes the case sensitivity for email logins.

If the content of the message is of type `message/rfc822`, then support
downloading the body of the message and sending it off to the mail parsing
system, simulating a piped email.

Previously, if a message had a Content-Disposition header, then it could not
be considered as the body of the message.

If the mail received into the system has a content type of 'message/rfc822',
then unwrap the inner message and use it as the parsed email. Effectively,
assume the email was forwarded as an message/rfc822 attachment.

Previously, the subject was duplicated, which is really confusing

Exclude the auto-responding email from possible alerts sent to staff