* implemented joining two subpath at their selected end nodes
* added some helper functions like reversing a subpath,
  closing a specified subpath or finding a point in the path
* introduced a new type KoPointPosition do describe a path points
  position inside the path
* added setProperty, unsetProperty functions to the KoPathPoint
  to add or remove a single point property
* made some documentation updates

There are no commands yet to undo/redo the new functions. I am
working on them next.


svn path=/trunk/koffice/; revision=583648