Full year support

[g4b0]

It would be nice if a configuration should activate the full year mode, like the one in this example: http://multidatespickr.sourceforge.net/#full-year-demo

I think that multidatepicker should be displayed without needing to click on the input field, that should be an hidden field manipulated by the calendar.

[micschk]

That'd be sweet! I don't have time to add this, but a PR is welcome!