Split Util into 2D and 3D

Unfortunately, there is very little shared code.
There might be more if we were actually using shaders.
Debug: export Util modules, for loading in ghci
Remove reference to local-only Pretty printing
Add solids example with sphere, cylinder
Use NurbsSurface over R3
Silence hlint warnings
Silence hlint warnings in Backend
Make camera viewpoint, direction configurable
Move default camera position oblique to axes
Mention dependency branches