I have nice acquitances whose email addresses I would like to parse correctly, but they,
oddly, have chosen to use windows-1252 to encode their email address. In
mail.ParseAddress, any character encodings other than utf-8 and iso-8859-1 are not
handled.

It would be nice to support windows-1252 with a preference towards being able to plug
more charsets in. (Perhaps, with a similar interface as go.text/transform#Transformer.)

Example:

    str := "=?windows-1252?Q?Michael_Bo=DFlet?= <michael.bosslet@example.com>"
    a, err := mail.ParseAddress(str)
    if err != nil {
        log.Fatalf("%s", err)
    }
    log.Printf("%s", a)

This will crash, unfortunately.