Avoid field filling without bind value with controller

[luizfilipe]

• Sometimes you just want the component to be rendered initially without a initial value filled, so actually this behavior works when a range is used, however if you want to use a singleDatePicker the problem is exposed, without a initial value, angular-daterangepicker fills the field with the current date and pass this to bootstrap-daterangepicker without boundnd the value with the controller.