Attachment settings are now exclusively handled by the settings on the
ThreadEntry field on the ticket details form. Enabling attachments as well
as tuning attachment validation settings are all handled from the one place
now.

Only one file is supported at a time now; but at least the files are saved
and displayed in the event of validation errors.

This will allow for more complex widgets to be added as plugins which
include css and javascript media files without manually adding header or
footer lines.

Make sure the check is callable
Use call_user_func_array when calling user defined function

Add context to ticket state name (noun) and action (verbs)

Conflicts:

	include/class.forms.php

And allow for @context to add context to the bare string literal. For
instance,

    /* @trans, @context "noun" */ 'Open'

Would mark the string 'Open' translatable with context "noun".

Fix search backend to use the new statuses

On some setups, IE v10 on Windows 7 at least, text added to the Redactor
editor after an image is inserted (via the image popup dialog for instance),
will not be retrieved via the ::get() method and so will not be submitted
with the form submit button.

This patch introduces a workaround by manually calling ::sync() for the
Redactor when the submit button is pressed — just before the form is
submitted.

Turns out the canned response selections for the original message and the
last message were swapped.

Previously, if the quoted response mechanism was disabled, then outgoing
mail would also not include the message-id token. This breaks the
correlation of email to ticket-thread. Now, the message-id token is always
embedded in HTML emails even if the quoted-response removal system is
disabled.

(Turns out that the message-id token was always included in text bodies.)