Improved saving of line borders to ODF. The stroke-dash is requiered to be in office:styles in the styles.xml

So I added a new generic style type to KogenStyle.

There are several more of these office:styles as described in the ODF spec 14.14 which will requiere a style type defined.

TODO: Saving these styles should be done automatically imho, so that all the applications do not have to do it on their own.