Builder Build panel: redraw the bond-order and geometry icons; a periodic table button #323

Seen: the Builder toolbar's bond-order chooser (single bond: two grey balls and a line) and geometry chooser (tetrahedral centre) use the original low-resolution bitmaps. They are small, blurry when scaled and drawn in a style the rest of the toolbar no longer has.

Where: the bond icons (bond_single, bond_double, bond_triple, bond_aromatic, bond_metal and their _large forms) and the shape icons (linear, bent, trigonal planar, pyramidal, tetrahedral, square planar, trigonal bipyramidal, square pyramidal, octahedral, in 18/24/48 px) are XPMs in data/client/pixmaps, chosen in ShapeData::shapeToImage/shapeToSmallImage and the bond drop-down.

Proposal: redraw both sets as SVG and load them as wxBitmapBundle (the route the other redrawn icons use; tools/screenshots/icons.py renders them for review), so they are sharp at every display scale. Draw them in the viewer's own ball-and-stick style: shaded spheres, Jmol element colours (carbon centre, grey or white ligands), bond orders as one, two or three sticks, aromatic as a stick with a dashed partner, metal bond dashed. Same set used in the drop-down lists and on the toolbar button.