Attempting an SVG-only rewrite.

• 30% fewer characters in main js file
• no dependencies except D3
• fast!
• crisp!
• Futura renders correctly (as originally intended in Neary's), and so much crisper!
• no weird blurry artifacts around thick sharp lines

To me the code is also more legible, but, well, that's just cuz I wrote it, lol. I'll let others be the judge of that. Preferably an other who's apt to actually be developing charts for us.