Plus print[ln] with the ability to print struct values.

Note for language mavens: if a "..." function passes its argument
to another "..." function, the argument is not wrapped again.  This
allows printf to call fprintf without extra manipulation. It's good
but needs to go in the spec.

This code works:
///
package main

import fmt "fmt"
import os "os"

type T struct { s string; a, b int }

func main() {
	P := fmt.Printer();
	P.printf("%s = %d with float value %.4f\n", "hi there", 7, 123.456);
	P.println("hi there", 7, 123.456);
	P.fprintf(os.Stdout, "%s = %d with float value %.4f\n", "hi there", 7, 123.456);
	P.println(T{"x", 7, 234}, "end of struct", 8, 9);
}

R=rsc
DELTA=28  (7 added, 3 deleted, 18 changed)
OCL=18321
CL=18324