#23 Missing iso 8601 format

[Dario]

In DateObjectFactory there are several formats but I miss the ISO-8601 so used by javascript

I'd find useful to be able to register new date formats on app startup, so a method like
addDateTimeFormat (java.lang.String pattern){
dateFormats.add( new SimpleDateFormat(pattern) );;
}
would be nice

This is specially useful for users of Roo
ISO 8601 yyyy-MM-ddThh:mm:ss[.sss][Z|[+-]hh:mm]