Joda DateTime should be converted to java.sql.Timestamp, not java.sql.Date

The Joda DateTime parameter should be converted to a Timestamp so the time factor is not lost.  Converting to a java.sql.Date loses any time associated with the DateTime.

If it's desired to just save a Date, then a joda LocalTime should be accepted as a separate parameter and it can be converted to a java.sql.Date.

Additional change, open for debate:  
 - Should return a DateTime in UTC.  Otherwise timezone of the JVM is assumed, which could be problematic.