Comment 5 for bug 1430873

Updates 14004 and 14009 fix ellipses and rectangles with % values, respectively.

One more nastiness: Moving one node causes set() to be called for all attributes but update() is not called. This leaves the computed values where the unit is % (or 'em'/'ex') incorrect which means that the nodes corresponding to the attribute values are placed on the screen in the wrong positions. Also, undoing an action does the same thing. I've added 'viewport' to SPItem so that the viewport is cached. This can then be used in set() to calculate the correct computed values. One could image eventually preservering the use of % values as attributes are edited as the 'viewport' information is now available.