This allows files which are edited on the fly during deployment to be
tracked so that they are not unnecessarily deployed again in the next
deployment run. It also allows for more creative deployment strategies using
something like `git ls-files -s`

html: Balancing is important

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

9ae01bf2 turned off HTML balancing, however,
quoted response removal will create unbalanced HTML. That HTML will be
stored unbalanced and will require extra processing when displayed on the
ticket thread.

This patch adds balancing support using libxml if enabled, which will
balance HTML without corrupting the HTML like htmLawed will with balancing
enabled.

forms: Fix fail getting value of password field

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

Force wrapping on long words e.g base64 encoded string

search: Fix several small issues with search indexing

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

* Reindexing did not properly flush the last batch of items to the search
  therefore reindexing would always miss the last few items.
* Creating a new html thread entry with inline images resulted in empty
  search content
* HTML tag stripping in HtmlThreadBody::getSearchable() would result in
  missing white space between some words, resulting in poor searchable
  content

Which seems to be used by recent versions of Andriod OS. It appears to be a
synonym of `multipart/related`

Also, fix roundtrip encryption if the form name changes (which is based on a
user's session), and avoid saving a NULL value if the password is not
changed when a form is updated.

If navigating back to the ticket queue (after closing a ticket, for
instance), return to the queue previously viewed.

(Most notably is the mail from Outlook, which embeds block elements inside
of <font> elements.)

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>