Add some code to support vector icons in PDFs and SVGs. Disabled for now

Unfortunately there seems to be a bug in Qt - when rendering SVG icons
that contain gradients (fading to transparent - like the class icon)
there is a thick black outline being rendered.
Change the color of primitive types.
Change the Png screenshot scale to 8x.
Minor improvements to the code contracts test code.
Make it possible to use short action shortcuts when even longer exist.
Fix a bug with destroying the cursor's owner item but leaving the cursor
Add a generic remove item quick action
Make some methods of AttributeChain const
Show names of compositenode children in the quick action prompt