Support the Uyghur translation

[nacin]

The Uyghur translation (ug_CN) bends over backwards to be compatible with WordPress. Because there is so much going on here, I need to pull it out into its own ticket.

Given the complexities here (I will post a diff shortly), and because they compose about 1/10th of one percent of non-English downloads, I don't see this happening for 3.4.

[nacin]

Diff against 3.3.1. I reverted all changes made irrelevant by #19598 or elsewhere. I also left out the font files, which you can find at ​http://i18n.svn.wordpress.org/ug_CN/trunk/dist/wp-content/languages/.

[moorshidi]

Uighur has two big problem on Web Browser:

1. Character connectivity: some Uighur character cannot connect properly in some OS, even in Arial or Tahoma. It is a font problem so we must use our own font.
2. Text Input: even an Uighur Input Method added from Windows Vista, but the 70% of Uighur have to use Windows XP with IE6 in China. User unable to input Uighur characters on this OS. So we must add a keyboard hook in the purpose of Uighur text input.

Up to now, these problems solved by Uighur Translation Team every time.

[SergeyBiryukov]

The latest version on ​https://ug.wordpress.org/releases/ is 4.1, and it doesn't have any of these changes (they were removed in ​https://i18n.trac.wordpress.org/changeset/22817).

Also, the home page of the site says that the translation is no longer active.

Feel free to reopen if still relevant.