Multilanguage Support via gettext

- added gettext encapsulations to all texts i thought necessary
- added fallback function for the case that the gettext extension isn't loaded
- added browser language detection
- added gettext to the list of optional extensions in setup
- rewritten some of the texts to use sprintf instead of appending strings
- added german translation file
- removed mark_overdue-confirm from cannedresponses.inc.php

extend multi language support and a fex fixes

- Better detection of translation files
- Added functionality to redirect language codes (see redirecting
language codes)
- Ticket Status can be translated
- The Datepicker can be translated
- Extended functionality of 'testlang.php' to show what language code is
used to translate

Forgotten to apply a patch from RC5 to RC6

- Forgotten to change $var to $vars in line 380 of class.mailfetch.php
- Removed unneeded comment

Added php_gettext as primary translation engine

- Added php_gettext support (thanks to Danilo Segan and Steven
Armstrong)
- php_gettext is now the primary translation engine
- Extended language detection functionality

Add error/misconfiguration checks and fix undefined variables

Starting with osTicket 1.8.1, users must receive an email and follow a link
in the email to get access to the ticket. With this new option, the email
verification step can be avoided in osTicket 1.9, because access is now only
granted to exactly one ticket.

Previously, they were displayed in seemingly random order, did not honor
proper nesting, or declared sort order.

In both the client and staff interfaces, where the URL and request
parameters were echo'd back without any escaping

In both the client and staff interfaces, where the URL and request
parameters were echo'd back without any escaping

Add original and last message quotes to canned responses

As previously implemented, only "Department and group members" could be set

Otherwise, no column will be added to the %ticket__cdata table and the
ticket queue pages will be crashed (empty).

Use the topic associated with the email if any, and the topic defined as the
system default as the last resort. In either case, the form associated with
the help topic will be added to the ticket, but no data will be put into the
form fields.

The default mode going forward will be to insert when Rich Text support is
enabled and append otherwise. To clear the draft the user can simply click
reset or delete draft icon on the bar.

Enable delete draft option on reply & internal note boxes for consistency.

The user preview tool tip and edit dialog use the same user template.
Editing on preview mode resulted in partially hidden edit form. This fix
adds ability to popup a dialog modal on edit while on preview mode.

On the user profile page, the link to view the organization now triggers a
popup dialog which allows for changing and editing the organization directly
from the user profile page. An additional [Manage] button is added to the
dialog to allow redirect access to the organization page.