#42 created ISO8601JXDatePicker

ISO8601JXDatePicker is a subclass of JXDatePicker, which uses ISO 8601
(YYYY-MM-DD) as its main format.
 #42 make use of ISO8601JXDatePicker

Replace JXDatePicker with ISO8601JXDatePicker.
Merge branch 'feature/42-iso8601-dates' into dev