Streams refactoring

Src/Data/Myc.Data.Stream.pas

@@ -275,8 +275,12 @@ begin
         for j := 0 to High(AConfig[i]) do
         begin
             // Extract the specific column series
-            FSourceSeries[n] := ASources[i].Series.Fields[AConfig[i][j].Key];
+            var m := ASources[i].Series.IndexOf(AConfig[i][j].Key);
-            inc(n);
+            if m >= 0 then
+            begin
+                FSourceSeries[n] := ASources[i].Series[m];
+                inc(n);
+            end;
         end;
     end;
 end;