CJuiDatePicker extended for more/better language support

Comparing #1 with #2

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The number of languages supported by the standerard CJuiDatePicker implementation is limited and the language code to use is different from the application's language code.
This Wiki shows how to improve on that.

Basically, the derived implementation of the CJuiDatePicker class below does two things:
1. Convert the language code to the one required by the CJuiDatePicker;
2. Reference other locality files that I got from another open source project ([Kooboo](https://kooboo.codeplex.com/releases/view/117778 "Kooboo")).
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