validator: Verify MX record of email addresses

Peter Rotich <peter@osticket.com>

session: Add support for Memcache as a session backend

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

db: Drop tables before adding and renaming

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

fast fix for deployment on windows #2032 

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

include: Fix typo

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

If the email address in use by the end user is not valid, display a warning
on the ticket view page. This allows an agent to easily flag potential spam
or correct a legitimate email address before sending a response and
receiving a bounce notice.

This allows detection of some incorrectly-typed email addresses before
tickets, users, and agents are created.

The PHP session system will hold a lock on the session until it is released.
It is important to release the session before performing long-running tasks
so that further requests from the agent are not locked.

orgs: Touch `updated` time when custom data is updated

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

Logged user fix

oops: Fix bad HTML entity #2

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

Fix image CID rewrite for some pasted images

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

users: Update information on CSV import

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

i18n: Translate gb2312 to gbk charset

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

html: Ensure text internal note preserved

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

Preserve text formatting on the internal note posted to a new ticket by
staff if HTML thread is disabled.

This is necessary for some mail clients which indicate encoding in GB2312
but actually use GBK encoding.

tnef: Fix various TNEF processing issues

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

email: Properly detect bounce message with alternative content

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

fix translation for "Add new list"

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

Fix a few translatable phrase issues

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

mailer: Embed the Message-Id token in @class

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

Ensure consistent name formatting for agents and end users

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

email: Support agents emailing as collaborators

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

If osTicket was improperly or incompletely upgraded, then some tables may
exist which should otherwise not exist. This patch assists the upgrade
process by dropping the tables which should not exist prior to adding or
renaming tables.

This correctly handles a bounce message with the following layout:

multipart/report; report-type=delivery-status
    multipart/alternative; differences=Content-Type
        text/plain; charset="us-ascii"
        text/html; charset="us-ascii"
    message/delivery-status
    message/rfc822

Fixes #1854