Fixed getDayOfYear and getWeekOfYear behavior

The old code was return date that was off by one for getDayOfYear and the getWeekOfYear was returning a double and overwriting the document.

I am not sure how you want to address the minified version in jquery.datetimepicker.js. I can include my yui-compressed version or you can re-minify yourself.

Let me know if you have questions or comments.