summary of diff --git  a/main.go b/main.go

- Add `io` to import secondary list in `main.go`
- Remove the short forms `Pl` and `Pf` from the variable list
- Add shortcuts for `Stdin`, `Stdout`, and `Stderr` in variable list
- Implement `SetStdio` function to allow redirection of stdin, stdout, and stderr
- Redefine `Pl` and `Pf` as functions that allow redirection of stdout when `Stdout` is set to a desired `io.Writer`