Exclude user lookup done on ticket create from Recent Searches

This addresses an issue where some Vimeo videos are not being sent in
Agent’s responses. This adds `player.vimeo` to the sanitize method’s
iframe section so that the iframe tag is not stripped.

* Export all exportable fields by default - for all queues + adhoc searches
* Export Due Date as well as SLA Due Date

Add ability to add sticky export fields for queues.

* Due date vs. SLA due date
* Misc. datetime fixes

Add ability to edit individual fields without the need to mass-edit all
fields.

Conflicts:
	include/class.thread.php
	include/class.ticket.php

Add support auto email-based auto-referral. This will happen if an email is
sent to multiple departments. For example an email with TO: support &  CC:
billing will result in the ticket getting routed to "support" department and
"billing" getting a referral of the same ticket. This allows both departments
to have visibility of the ticket - which is not possible at the moment.

Move referral checking to thread class

cron: Delete Expired Sessions

Move referral checking to thread class

Refer ticket to current assignee on reassignment
Refer ticket to current department on transfer

Add the initial concept of thread (tickets & tasks) referral.

* Agent & Team
Referring a ticket to an agent or team - is just like assignment without
actually assigning. If referred agent doesn't have access to the ticket's
department then they'll only have view access.

* Department
This is like assigning a ticket to the entire department. Meaning agents who
have access to the referred to department will now see the ticket - what
they can do with the ticket will depend on the assigned role in that
particular department.

It's important to note the ticket will technically be still the
responsibility of the primary department. Transferring the ticket is the
sure way to relinquishing the responsibility.

* Auto Department Referral via email
This will happen if an email is sent to multiple departments. For example an
email with TO: support &  CC: billing will result in the ticket getting
routed to "support" department and "billing" getting a referral of the same
ticket. This allows both departments to have visibility of the ticket -
which is not possible at the moment.

This addresses issue 3815 where searching by User's phone number doesn't
work in v1.10. This adds phone number search capabilities for the User
Directory and User Search popup in v1.10.

Limit the departments based on Agent's access

Refer ticket to current assignee on reassignment
Refer ticket to current department on transfer

Add the initial concept of thread (tickets & tasks) referral.

* Agent & Team
Referring a ticket to an agent or team - is just like assignment without
actually assigning. If referred agent doesn't have access to the ticket's
department then they'll only have view access.

* Department
This is like assigning a ticket to the entire department. Meaning agents who
have access to the referred to department will now see the ticket - what
they can do with the ticket will depend on the assigned role in that
particular department.

It's important to note the ticket will technically be still the
responsibility of the primary department. Transferring the ticket is the
sure way to relinquishing the responsibility.

* Auto Department Referral via email
This will happen if an email is sent to multiple departments. For example an
email with TO: support &  CC: billing will result in the ticket getting
routed to "support" department and "billing" getting a referral of the same
ticket. This allows both departments to have visibility of the ticket -
which is not possible at the moment.

This addresses issue 3815 where searching by User's phone number doesn't
work in v1.10. This adds phone number search capabilities for the User
Directory and User Search popup in v1.10.

Limit the departments based on Agent's access

Currently only windows of a specific number of days is supported. Things
like `last month` are much more complex.