Added dateOrder prop to have configurable columns

[zeel]

By default dateOrder will be same as old behaviour which for DATETIME mode, it will be ['y','M', 'd', 'H', 'M'] if use12Hours is true then ['y','M', 'd', 'H', 'M', 'ampm']

where below is mapping for corresponding constants const DAY_ORDER = 'd'; const MONTH_ORDER = 'M'; const YEAR_ORDER = 'y'; const HOUR_ORDER = 'H'; const MINUTE_ORDER = 'm'; const AMPM_ORDER = 'ampm';

User can give dateOrder in any manner.

for example for showing day before year, it should be ['d', 'M', 'y', 'H', 'M', 'ampm']