Also complete the translation client-side

Including language-specific attachments

Drafts now are placed directly into the HTML response. The response contains
the draft information as well as the original content saved in the database
for the content being modified. The draft itself is placed into the redactor
box rather than the current content.

This patch also reduces some of the [Draft Saved] notices where there is no
content or the content has not yet been modified.

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

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

On validation errors, `$faq` will be set to something non-null, like
`false`, but will not be an instance of a Faq article.

- Proofread large portion of help tips.
- Implement help tip links in YAML files.
- Fix GUI spacing of some elements.
- Add <label> tags to a few form elements.

Fixes oversize image display to be resized in both the ticket thread and
the redactor editor in (at least)

  * Ticket-view boxes
  * Client new-ticket form
  * Staff new ticket
  * Page add/edit
  * FAQ add/edit
  * Canned response add/edit

Fixes osTicket/osTicket-1.8#247

Fixes #198

Process inline attachments in thread entry and support inline images in
piped emails

Support inline images across the system, with draft support

Migrate to a single attachment table
    That way we don't need a new table for everything we need to attach an
    inline image to (like a signature, for instance)

Add richtext support for internal notes

Implement images on site pages

* Image paste in Redactor
* Make non-local images optional
* Placeholder for non-local images
* Fix local image download hover
* Don't re-attach inline images