Implement missing options of bootstrap-datepicker

- [x] Add more tests
- [ ] [`calendarWeeks`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#calendarweeks)
- [ ] [`clearBtn`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#clearbtn)
- [ ] [`daysOfWeekDisabled`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#daysofweekdisabled)
- [ ] [`endDate`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#enddate)
- [ ] [`forceParse`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#forceparse)
- [ ] [`keyboardNavigation`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#keyboardnavigation)
- [ ] [`minViewMode`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#minviewmode)
- [ ] [`orientation`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#orientation)
- [ ] [`startDate`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#startdate)
- [ ] [`startView`](http://bootstrap-datepicker.readthedocs.org/en/release/options.html#startview)