This adds basic support for nesting (#17). It does not swap fill/stroke colors based on the position of the nesting box, though. It also only nests a symbol in the eye creature and "bonkers" complexity setting for now--support for nesting in complexity levels 1-4 is forthcoming.
The nested symbol is essentially uniformly scaled as much as possible without extending outside the boundaries of its parent's nesting box.
Atul Varma