Fixed bug when no options binding is given

Added refresh to the bindingHandler

#143. #183, #89, #78. But not perfect. Select all option needs to be updated depending on the filter.

Modified click and touchstart events to support shift key multi selection.

Performance for select-all.

Added refresh to the bindingHandler to support clearing/modifying of the
bound observable.

Modified click and touchstart events to support shift key event , not is possible to multiselect values keeping shift pressed

Add support for show/hide events.

Add 'numberDisplayed' default to multiselect and use that to determine w...

Add function to customize label of itens.

Add 'numberDisplayed' default to multiselect and use that to determine when to display a number in the select box

removed left-over console.log

onChange callback context

Remove console.log call