Update Date.js

FIX for issue #19 datepicker part
extends the override for pickerslot titles, not only the months array. And there's an option to define the slotorder for differnt date formats.
This is a valid picker config:
picker: {
	useTitles: true,
	locales:{
		dayText: 'fields.day',
		monthText: 'fields.month',
		yearText: 'fields.year',
		months: 'months',
		slotOrder: 'fields.slotOrder'
	}
}
with a template.json:
{
	"fields": {
		"day": "Day",
		"month": "Month",
		"year": "Year",
		"slotOrder": "['day', 'month', 'year']"
	},
	"months": {
		"1": "January",
		"2": "February",
		"3": "March",
		"4": "April",
		"5": "May",
		"6": "June",
		"7": "July",
		"8": "August",
		"9": "September",
		"10": "October",
		"11": "November",
		"12": "December"
	}
}