1. Fixed a typo in news_add.php in a variable name which was causing a warning.
2. Fixed a problem where admin was not able to edit site-wide news (if All Projects is selected).
3. Added support for $g_private_news_threshold, defaulted to DEVELOPER.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1115 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9