* Design affine transforms in geom & use them instead of matrices when appropriate
* Add more pixmap fonts
* Design ui system
* Add color utilities
* gfx::painter should support normals & minimal lighting (maybe split into separate 2D & 3D painters?)
* pcg: add clean Generator, Sampler & Pixmap processor concepts, uniformize interfaces, be type & dimension agnostic when possible
* pcg: add more vector & point distributions