ToResult for Mainable newtype wrapper
rename function to avoid conflict with coming general function
NumGrid -> IntGrid
Show instance for Grid
Ord and Eq instances for Edge, to allow sorting and nubbing
use the pixel perfect grid for drawAreaGridG
drawing int grids
drawing shaded cells
drawing dual edges (e.g. masyu loop)
Another approach to yaml parsing
drawing different puzzle types
draw "any" supported puzzle type (example)