[ci skip] Add test of short int to see if there's any obvious places for overflow (none are obvious, but no guarantees they still aren't there). Print basic information about the test to console so that failures are easier to track down.

include/boost/integer/extended_euclidean.hpp

@@ -14,6 +14,7 @@ namespace boost { namespace integer {
 // From "The Joy of Factoring", Algorithm 2.7.
 // Should the tuple be a named tuple? Is that possible?
 // Solves mx + ny = gcd(m,n). Returns tuple with (gcd(m,n), x, y).
+// Is this the natural ordering?, or must people simply have to read the docs?
 template<class Z>
 std::tuple<Z, Z, Z> extended_euclidean(Z m, Z n)
 {