wumpus-core

Copperbox revision 1693.

Second round of changes to move SVG hyperlinks in the syntax tree. This commit removes the old code and tidies up the data types.

One outstanding problem is that because XLinkGroup groups Primitives together, primitive transformations don't work as they used to. Primitives used to support some transformations that were sensible on single elements whilst not being strictly affine (because there was no notion of a frame at this level in the syntax).

An XLinkGroup could map transformations on the elements it groups, but because grouped primitives have some notion of coordinates I feel this suggests proper affine transformation when it wouldn't be. Certainly the API needs some more thought.