datetime editor examples

## Extended handling of date, time and datetime-local type fields.

Works with both string and integer data types. (If integer is used, the date will be returned in epoch format)

Adds support for setting "placeholder" through options.

Has optional support for using flatpickr datepicker.

All flatpickr options is supported with a few minor differences.

- "enableTime" and "noCalendar" are set automatically, based on the data type.
- Extra config option "errorDateFormat". If this is set, it will replace the format displayed in error messages.
- It is not possible to use "inline" and "wrap" options together.
- When using the "wrap" option, "toggle" and "clear" buttons are automatically added to markup. 2 extra boolean options ("showToggleButton" and "showClearButton") are available to control which buttons to display. Note: not all frameworks supports this. (Works in: Bootstrap and Foundation)
- When using the "inline" option, an extra boolean option ("inlineHideInput") is available to hide the original input field.
- If "mode" is set to either "multiple" or "range", only string data type is supported. Also the result from these is returned as a string, not an array.