I hope you don't mind @awernle , but I went ahead and started this change we discussed because I need it in place to test some other ideas I have.
min_count keyword to the AvergeAlgorithm's init() method;self.min_count = arguments.average_min_count in configure() method;min_count, but now it defaults
to a requirement that all inputs be valid (this modified a recent merge
by @awernle that only required that any inputs be valid;