Label text should not be prepended when rendering an checkbox element in a horizontal form

Currently when you render a checkbox element in a horizontal form the text of the label is prepended before the markup of the checkbox element. This is not as expected, see following links:

* http://neilime.github.io/zf2-twb-bundle/2.0/demo.html#forms
* http://getbootstrap.com/css/#forms-horizontal

Screenshot of what currently happens without this fix:
![screen shot 2014-01-17 at 10 40 13](https://f.cloud.github.com/assets/145226/1939133/8d4228a2-7f5b-11e3-9396-7c89aa550b45.png)