hist1d_confidence bug fix

Function returned wrong order of results (and index was mixed up)

src/plot/distribution_matrix.sl

@@ -53,7 +53,7 @@ define hist1d_confidence (lo, hi, h)
 
   if (qualifier_exists("index"))
     return jj,ii;
-  return hi[jj], lo[ii];
+  return lo[jj], hi[ii];
 }
 %}}}