This patch includes a slight database migration, and adjusts the
functionality of a few core components.

  * Move collaborators from the ticket to the thread.
    This concept allows collaborators on any object which has a thread,
    including tasks.

  * Add flags to the thread entry
    This will allow flagging thread entries for different purposes.
    Initially this can be used to flag the original message of a thread in
    case a ticket / thread is created without an initial message.

  * Lock becomes more of a utility
    The lock is now disconnected from the ticket and is a separate utility.
    Separately, the ticket and task objects can have a reference to a lock
    object. Furthermore, when submitting some activities to tickets, the
    lock is verified to be owned by the respective agent, and the lock code
    must match a current lock code. The code is rotated on each acquire()
    call to guard against double submissions.

  * Collaborator is an ORM model
    The TicketUser class is broken up now so that the collaborator instance
    can exist apart from a ticket. Email message ids are now generated for
    collaborators without respect for a ticket so that collaborators can be
    properly supported on any thread.

This patch rebases filters into a row-based layout and redesigns the filter
apply method to be more extensible. It also redesigns the UI to be more
dynamic and to allow for actions to be added without database modification
and actions can also have complex configurations.

Help topics can now specify one or more additional forms to be included on
the help topic and can also specify the sort order of those forms.
Furthermore, individual fields can be disabled per help topic, so that
unnecessary fields can be omitted when necessary, per help topic.

The disabled flag is recorded along side the field data so that the field
will not be accidentally added to the form later automatically. There is no
interface in this commit to enable a field which was disabled by the help
topic when ticket was created.

Support duplicate names in different hierarchy
Save path on add/update
Show full department name on transfer

Introduce the concept of tasks. Tasks are to do list that can be attached to
any object e.g Ticket.

Use generic attachment table for all attachments system-wide.
Drop thread entry attachment table

Detach conversation thread from ticket to make it more generic. Any object
can now have its own thread complete with entry type and attachments.

Use generic attachment table for all attachments system-wide.
Drop thread entry attachment table

Detach conversation thread from ticket to make it more generic. Any object
can now have its own thread complete with entry type and attachments.

Introduce the concept of role-based access for agents.

Introduce the concept of role-based access for agents.

The commit also renames some fields in department table.

This is necessary so we can consolidate various settings and permissions
into one bit mask field.

And manage it with updates to tickets. This will ease the sorting and
display of tickets based on the time of last update in the ticket queues

This will contain the effective due date of the ticket — either the due date
or the estimated overdue time of the ticket based on the SLA settings. It
will be maintained with ticket updates.

orm: Add greater support for expressions in order_by

Also, autodetect the endusers timezone using the jstimezonedetect Javascript
library.

This patch adds support for automatic date and time formatting based on a
selection of locale. The locale can default to the system or user specified
language+locale, or can be elected separately. For instance, English
speakers can pick between US, GB, and many other English speaking locales.

This also removes the need of the %timezone table and uses the timezonedb
built into PHP 5.3+. User's can now select from a much longer list of
database and no longer need to deal with the DST checkbox.

Implement the logic to set status

Help topics and filters can override the default status

DynamicList initial data

Add TicketStatus class and ticket_status table

Previously we required an account to associate a user to an organization.