Fixed code smells

protocol/aprs/base91.go

@@ -2,7 +2,6 @@ package aprs
 
 import (
 	"fmt"
-	"strings"
 )
 
 func base91Decode(s string) (n int, err error) {
@@ -18,6 +17,7 @@ func base91Decode(s string) (n int, err error) {
 	return
 }
 
+/*
 func base91Encode(n int) string {
 	var s []string
 	for n > 0 {
@@ -27,3 +27,4 @@ func base91Encode(n int) string {
 	}
 	return strings.Join(s, "")
 }
+*/