Fix suggestion for DateRangePicker Issue (Issue #266)

This pull request is related to Micka1066's recent issue (#266) where he points a misbehaviour in the script registration of the DateRangePicker widget.

To fix the issue, I altered the script registration method and removed the specific ClientScript position so that the registration can now use the default configuration.

Hope this will be helpful.
(also thanks to Micka1066 for spotting the problem)

Frdric