Add empty yearSuffix for Dutch translation to remove Chinese character

This will remove a Chinese character that's being shown if both changeMonth and changeYear are enabled.

![screen shot 2014-07-10 at 15 50 00](https://cloud.githubusercontent.com/assets/1431100/3539615/23c14632-083c-11e4-8145-52538a456437.png)

The yearSuffix parameter is also in the default translation of jQuery UI 1.8.16. (http://jqueryui.com/download/all/)