Intent-to-implement: Date Picker Component.

Hey guys, This is Ziwei. I intend to implement a Date Picker Component into HIG library. It can be used to select a date or a time with date. It will be a useful addition to HIG.

The current features I am thinking to implement including
- using props to specify the date format, locale
- default style should adhere to HIG design guideline
- specify the boundaries of date to be selected
- specify certain dates or range of dates to display a short message (eg. error message)

I am looking to get some inputs and ideas. So feel free to discuss here.