Add basic information and utils for RTL scripts

Change-Id: Ie01b58cd3627e8f0bf726f0bb296bffb25efcbb5

lib/jquery.uls/data/langdb.yaml

@@ -554,6 +554,9 @@ scriptgroups:
   SignWriting: [Sgnw]
   NativeAmerican: [Cher, Cans]
 
+rtlscripts:
+  [Arab, Hebr, Syrc, Nkoo, Thaa]
+
 regiongroups:
  # north-america
   NA: 1

lib/jquery.uls/src/jquery.uls.data.utils.js

@@ -329,4 +329,13 @@
 			autonymB = $.uls.data.autonym( b ) || b;
 		return ( autonymA.toLowerCase() < autonymB.toLowerCase() ) ? -1 : 1;
 	};
+
+	/**
+	 * Check if a language is right-to-left.
+	 * @param string language code
+	 * @return boolean
+	 */
+	$.uls.data.isRtl = function( language ) {
+		return $.inArray( $.uls.data.script( language ), $.uls.data.rtlscripts ) !== -1;
+	};
 } )( jQuery );