This patch adds support functions to the widget-utils module:
transformFromRectToRect:
   returns transform to map coords from one rectangle to another
constrainRectToRect:
   returns rectangle scaled to fit another while preserving aspect ratio

This patch makes some improvements to the svgpath widget by recording the
values used to render the transformed svg path and only recomputing them when
necessary.

This patch adds a release note for the improvement to the rendering
performance of the svgpath widget