Added functionality so the datepicker is aware of it's location within the browser window

If part of datepicker will be below the browser window, it will now display above the textbox.  If it is going to go past the right side of the window it will position itself to be right aligned with the datepicker
![screen shot 2013-12-03 at 1 23 50 am](https://f.cloud.github.com/assets/119142/1662301/ad84c8b8-5bfc-11e3-95bc-e57c9a8c091c.png)