Fix incorrect encoding issue:

Output to response by authenticationSuccessHandler make character encoding fix to ISO-8859-1.

Test case
=======
I 'm setup a TestController. 
https://gist.github.com/pphetra/9084508

When api called without token. The encoding is 'UTF-8'
![screen shot 2557-02-19 at 8 29 29 am](https://f.cloud.github.com/assets/1422/2202576/6393706e-9906-11e3-917d-d27771dd9d0c.png)

When api called with token. The encoding is change to ISO-8859-1
![screen shot 2557-02-19 at 8 30 52 am](https://f.cloud.github.com/assets/1422/2202582/86428fb4-9906-11e3-8e9f-a09d4fa0f936.png)