[Python-3000] [Email-SIG] fix email module for python 3000 (bytes/str)

[Bill Janssen]

>  base64MIME.decode() and base64MIME.encode() should accept bytes and str
>  base64MIME.decode() result type is bytes
>  base64MIME.encode() result type should be... bytes or str, no idea
> 
> Other decode() and encode() functions should use same rules about types.

Victor,

Here's my take on this:

base64MIME.decode converts string to bytes
base64MIME.encode converts bytes to string

Pretty straightforward.

Bill