Support utf-8 strings

using qrcode_UTF8.js from
https://github.com/kazuhikoarase/qrcode-generator,

src/qrcode.js

@@ -472,13 +472,39 @@ var qrcode = function() {
     //---------------------------------------------------------------------
 
     qrcode.stringToBytes = function(s) {
-        var bytes = new Array();
-        for (var i = 0; i < s.length; i += 1) {
-            var c = s.charCodeAt(i);
-            bytes.push(c & 0xff);
-        }
-        return bytes;
-    };
+		// http://stackoverflow.com/questions/18729405/how-to-convert-utf8-string-to-byte-array
+		function toUTF8Array(str) {
+		  var utf8 = [];
+		  for (var i=0; i < str.length; i++) {
+			var charcode = str.charCodeAt(i);
+			if (charcode < 0x80) utf8.push(charcode);
+			else if (charcode < 0x800) {
+			  utf8.push(0xc0 | (charcode >> 6),
+				  0x80 | (charcode & 0x3f));
+			}
+			else if (charcode < 0xd800 || charcode >= 0xe000) {
+			  utf8.push(0xe0 | (charcode >> 12),
+				  0x80 | ((charcode>>6) & 0x3f),
+				  0x80 | (charcode & 0x3f));
+			}
+			// surrogate pair
+			else {
+			  i++;
+			  // UTF-16 encodes 0x10000-0x10FFFF by
+			  // subtracting 0x10000 and splitting the
+			  // 20 bits of 0x0-0xFFFFF into two halves
+			  charcode = 0x10000 + (((charcode & 0x3ff)<<10)
+				| (str.charCodeAt(i) & 0x3ff));
+			  utf8.push(0xf0 | (charcode >>18),
+				  0x80 | ((charcode>>12) & 0x3f),
+				  0x80 | ((charcode>>6) & 0x3f),
+				  0x80 | (charcode & 0x3f));
+			}
+		  }
+		  return utf8;
+		}
+		return toUTF8Array(s);
+	  };
 
     //---------------------------------------------------------------------
     // qrcode.createStringToBytes