* added com::sun::star::table::TableBorder2 with
  com::sun::star::table::BorderLine2 members
* added optional com::sun::star::table::BorderLine2 properties to
  com::sun::star::table::CellProperties service
* changes in Calc
  * support TableBorder2, additionally to TableBorder
  * reverted change that made all BorderLine properties operate with
    BorderLine2 structs
  * instead support both, BorderLine and BorderLine2