Show Nim: Pixie, a fast 2D vector graphics library we are excited to share!

[michy]

Comparisons show huge differences in speed between blend2d and cairo, at least 
for most examples: <https://blend2d.com/performance.html> So _still a bit 
slower than blend2d " does not really harm. But *slower than Cairo_ is a 
different thing and asks for optimizations. Speed in b2d is mainly due to the 
jit-compilation step, if I got it right.