Add option to control hover text fade distance and range.

No UI yet.

indra/newview/skins/default/xui/en/floater_preferences.xml

@@ -174,6 +174,11 @@ https://accounts.secondlife.com/change_email/
          label="Skinning"
          layout="topleft"
          name="skins" />
+        <panel
+         filename="panel_preferences_interface.xml"
+         label="Interface"
+         layout="topleft"
+         name="interface" />
     </tab_container>
 
 </floater>