feat(timepicker): modify the code to align with DatepickerPopup;

Hi, the timepickerPopup is the exact control that I'm looking for.
I did some code change to make it be more aligned with datetimePickerPopup and also added the isOpen field to the scope so that the open state can be altered from outside.
There's some slight bugs when parsing input text, when changing the content in the input, the timepicker doesn't change.

Feel free to kindly review and merge the change. Thanks.