update versions of external dependencies
midway through refactor
changing vis.graph to graph.vis
fixing graph_axes

can’t append an axis to an axis!
cleanup, renaming
remove old graph_axes file too
indifference curves, dropline refactor
delete unused files
nearly complete

need to update logic in text checking for equilibrium
deleting old files
Merge pull request #10 from cmakler/indifference-curves

Indifference curves