[PATCH] Add mactext extension module

[Jesse Glick]

OHASHI Hideya wrote:
> +# mactext.py - LF <-> CR translation utilities for Mac or OS-9/68K users

This is similar to win32text and copies some of its code but not 
consistently. I guess they should be consolidated somehow.

> +def macdecode(s, cmd, **kwargs):
> +    if util.binary(s):

win32text now (again) uses: '\0' in s

> +    return macdumbdecode(s, cmd, **kwargs)

win32text prints a warning for text files already using \r\n in the repo.