[CM] Bug in read

[Woody Douglass]

All,

I may have found a bug in `read`

consider the following

```
(define (strtest)
    (let* ((num "#xff")
           (in (open-input-string "#xff"))
           (val (read in)))
       (= (port-position in) (length num))))
```

(strtest) defined above returns #f, i think it should return #t
I think reader macros are increasing port-position to what the position
would be post-macro, not pre-macro

Has anyone seen this?

Thanks,
Woody Douglass