* Fix translation of pages
  * Localize client thank-you page on new ticket
  * Fix adding new category
  * Fix crash on staff login when upgrading from < 1.9
  * Don't show self locks on ticket queue pages

This allows for things like related COUNTs and such:

```php
ThreadEntry::objects()->annotate(
    'attachment_count'=>Aggregate::COUNT('attachments')
    )
    ->filter(array('attachments__type__contains'=>'image/'))
    ->filter(array('attachment_count__gt'=>0));
```
This would find all thread entries with at least one image attached.

Move the attachments to the sidebar, add the concept of language-specific
attachments. Add a sidebar to the front page. De-emphasize the "open new
ticket" button. Add a knowledge base search feature to front page and also
add the concept of "featured" articles and categories on the front page.

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