made supervisors more efficient
moved mutate functions into their own module
moved crossover functions into their own module
moved breed and fitness functions to their own modules
moved worker computations into its own module
added zipper list module
did some dijkstra optimization
added zipper_trees module with function to convert gb_tree to zipper tree
added functions to move focus up, left and right in the zipper tree
added get and set functions to zipper tree
added zipper nary trees module with some basic functions
added tests for zipper list; added commands to zipper nary tree
got all zipper nary tree functions working