Added show method for Schedule
SwapDateSchedule field order; show method

* The stub field has been moved toward the end as this is least likely
to change.
* The SDS show method has been expanded.
Renamed MultipleFinCalendar to JointFCalendar
Renamed SingleFinCalendar to SingleFCalendar
New method to join SingleFCalendars

Using the MultiFCalendar() constructor is a bit too verbose. `join`
will be a bit easier.

Also fixed sub typing of AU & EU calendars from previous commit
Shortened some function defs