Make JSON.stringify not quote non-ASCII characters. Fix bug 855.

src/json.js

Index: src/json.js
diff --git a/src/json.js b/src/json.js
index e7ec6100e56f04379178e1a84f6755ad82ea019f..5dd776899b6f942d5d0e795dd373be7df924de30 100644
--- a/src/json.js
+++ b/src/json.js
@@ -68,15 +68,13 @@ function JSONParse(text, reviver) {
 }
 
 var characterQuoteCache = {
+  '\b': '\\b',  // ASCII 8, Backspace
+  '\t': '\\t',  // ASCII 9, Tab
+  '\n': '\\n',  // ASCII 10, Newline
+  '\f': '\\f',  // ASCII 12, Formfeed
+  '\r': '\\r',  // ASCII 13, Carriage Return
   '\"': '\\"',
-  '\\': '\\\\',
-  '/': '\\/',
-  '\b': '\\b',
-  '\f': '\\f',
-  '\n': '\\n',
-  '\r': '\\r',
-  '\t': '\\t',
-  '\x0B': '\\u000b'
+  '/': '\\/'
 };
 
 function QuoteSingleJSONCharacter(c) {
@@ -95,7 +93,7 @@ function QuoteSingleJSONCharacter(c) {
 }
 
 function QuoteJSONString(str) {
-  var quotable = /[\\\"\x00-\x1f\x80-\uffff]/g;
+  var quotable = /[\\\"\x00-\x1f]/g;
   return '"' + str.replace(quotable, QuoteSingleJSONCharacter) + '"';
 }