FIX: Process running state

src/un_process.pas

@@ -135,7 +135,7 @@ end;
 
 procedure TExProcess.Stop;
 begin
-  FStop:= FProcess.Terminate(-1);
+  FStop:= (not FProcess.Running) or (FProcess.Terminate(-1));
 end;
 
 procedure TExProcess.SetCmdLine(CommandLine: String);