wumpus-fresh

Copperbox revision 1639.

I've renamed the FreshIR module to be PictureInternal and added a Picture module to match Wumpus-Core.

Also I've added the new Picture constructors, though I haven't done anything with them yet. The salient difference from Wumpus-Core is that affine transformations are represented as syntax rather than an affine frame. This should mean I can manipulate the transformations more readily to convert into SVG's coordinate space.