Returns a sequence of the selected files including path information in
URL format, conform to Rfc1738.
If the user closed the dialog with cancel an empty sequence will be returned.
If the user closed the dialog with OK a list of all selected files will be returned.
@attention
Instead to the method getFiles() of base interface XFilePicker the new method return
full qualified URL's for every selected file.
Returns
A list of all selected file as complete URL's.
Notes for the implementation of a FileSave dialog:If there exists
a checkbox "Automatic File Extension" which is checked and a valid filter is currently selected
the dialog may automatically add an extension to the selected file name(s).