2014-04-25 v1.0 initial version
2014-05-03 v1.1 now with a BigInt variant for the clinically insane
2014-05-18 v1.2 now without the "must be a power of 2" side limit, if you don't mind noninteger return values
2016-01-02 v1.205 now links to Path::Hilbert::XS