Use $PYTHON in makefile
Don't use Python 3 syntax for keyword-only arguments
More points
Add modeline
Don't use Python 3 syntax "x, *xs = ..."
Don't use yield from
Do not rely on defaultdict from as_powers_dict

as_powers_dict() returned a defaultdict(list) instead of defaultdict(int).
Add code for when minsolve_linear_system is not available
Don't rely on int division yielding floats
Recast input points to float