Long term 'asVar' will be replaced with __toString function

Add routine to get ticket's recipients (owner + active collaborators)

The main intension is to have a predictable length and position of
the ids - obfuscation is a welcomed side effect.

Connect to logout signal and clear upgrader session on staff logout.

Conflicts:

	include/upgrader/streams/core.sig

Drop join to the user table
Use internal ticket id instead of ticket number

Add EndUser lookup by email to TicketUser - returns a decorated user

Make Clientession extends EndUser

Allow variable replacer to call __call functions

TicketUser class - Abstract class with auth token implementation
TicketOwner class - extends TicketUser

Add user ticket stats to EndUser class

Checks the session for authkey and asks the backend that generated it to
validate it and return authenticated user.

Add ability for backends to set authorization key (authkey) specific to the backend.
The authkey is tagged with the "id" of the backend that generated it.

authentication backend.

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

Monitor failed login attempts and enforce timeouts

  - StaffAuthenticationBackend - handles backends supported in staff panel
  - UserAuthenticationBackend - handles backends supported in user panel

Registering a backend at parent level (AuthenticationBackend) will make it
available to both panels.

This is necessary to force downstream classes to implement key required
functions.

Add variable replacer callback

is_callable will report ANY function as available

This is necessary because the system depends ticket priority to sort and
display ticket data.

Allow autocomplete on email address

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

Show extra forms for help topic first

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

Export custom fields with the ticket queue export

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

Fix subject ticket number matcher (again)

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

Use case-insensitive matching on email address

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

Collaborators

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