This commit further corrects issues where emails were being sent out with names being improperly formatted if the name format is set as 'Last, First' or if it has special characters.

This means Agents can no longer choose to add a BCC User while creating or responding to a Ticket.

This also means that if a User emails in a Ticket where someone is BCC'd, the Ticket will be created without the BCC'd User(s).

If an email is sent where the Department email is BCC'd, a Ticket is created for that Department and other Users in the email are added as Collaborators.

This also changes the response options for Agents. They now have the options to:
- Reply All (User + Collaborators)
- Reply to User (only the User)
- Do not Email Reply

(Previously the options were Reply All, Reply to User, Reply to CC + User, Reply to BCC, Do not Email Reply)

This commit updates a bunch of files and changes a lot of phrases. Basically it extracts "Internal error occurred" from existing phrases.
I've re-ordered the phrases so "Internal error occurred" is always at the end after the actual informative error message.

Example comparison before and after this commit:
Before: 1 Phrase: "Internal error: Unable to print to PDF"
After: 2 Phrases: "Unable to print to PDF." + "Internal error occurred"

Previously, the create method was used to create a new instance of an orm
model (which would later result in an INSERT when persisted); however, some
classes require or utilize varying parameters to their create() method,
which PHP7 considers an error. Methods in subclasses must be defined with a
calling signature compatible with the parent class.

This patch shifts the concept of model creation to the constructor. Now, the
constructor of ORM models is required to be compatible with that of
ModelBase class. Now that most models do not define a constructor, this is
much easier to control, and much more logical.

Also, remove an issue where assignments on a relationship field to an
instance of a super class of the foreign model would raise an error. This
was previously addressed by re-classing the instance in the
ModelInstanceManager::getOrBuild(); however that design would create
multiple instances of the same object in memory, which defeats one of the
primary design concepts of the ORM. This patch addresses the issue by
allowing super-classes of the declared foreign model in relationship
assignments.

This patch removes several of the internal notes posted to a ticket for
various events and replaces them with events added to a threads event chain.
The emails are still sent out as they previously were, but internal notes
are only added to the thread if an agent actually specified comments.

Move collaboration implementation to thread level

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.

Make Clientession extends EndUser

Allow variable replacer to call __call functions

Add token (authtoken) based authentication to User authentication backend.

Add variable replacer callback

Provide facility to set collaborator status on add.