UTF-8 encode strings before MD5 hashing

Author: curtisliu

src/amplitude.js

@@ -380,8 +380,8 @@
       }
 
       var md51 = function (s) {
-        var txt = '',
-          n = s.length,
+        s = UTF8.encode(s);
+        var n = s.length,
           state = [1732584193, -271733879, -1732584194, 271733878],
           i;
         for (i = 64; i <= s.length; i += 64) {