fix: incorrect position of datepicker when appendToBody=true
fix: incorrect position of datepicker when appendToBody=true

Calculate position of dropdown if appendToBody=true (reviously it has
right:0).
Also change 'click' to 'mousedown' in order to close dropdown when
pressing on scrollbars.

Gillardo/bootstrap-ui-datetime-picker,carlescs/bootstrap-ui-datetime-picker,carlescs/bootstrap-ui-datetime-picker,saike/bootstrap-ui-datetime-picker,Gillardo/bootstrap-ui-datetime-picker,saike/bootstrap-ui-datetime-picker