User-defined Date/Time format

[ctjacobs]

Without changing the format of the Date/Time data stored in the database, let the user choose how they want the Date/Time to be displayed. For example, if the user provides a formatting string like "%d %M %Y", PyQSO could display the date as "24 March 2014" (instead of "20140324", which is an example of how the Date is currently stored in the database).

Suggested by Paride Legovini.

[JoelMon]

Also can we have a separate field for start time and end time? Thanks!