Datepicker using Globalize 1.x

:boom: WIP...

The goal is to have Datepicker working with Globalize 1.x.

Depends on
- [ ] https://github.com/jquery/jquery-ui/pull/1316 `fnagel:calendar-value-pr`;

Todo
- [ ] Destroy translation data (weekHeader, prevText, nextText , datePickerRole, currentText). Create user options instead;
- [ ] Move `external/date.js` into `ui/` (see #1260 (comment));
- [ ] Fix RTL LTR direction (available at `cldr.main("layout/orientation/characterOrder")`, values are `left-to-right` or `right-to-left`);
- [x] Fix Use narrow day names (e.g., "ﺥ" EEEEE) if short (e.g., "ﺎﻠﺨﻤﻴﺳ" EEE) if too lengthy;
I never liked that we attempted to translate the language names. Anyone browsing our site has to have some level of English comprehension and I'm sure they can recognize their language written in English if they can read our docs and demo descriptions.