[Mono-list] Fix for StreamWriter (doh!)

[J. Perkins]

Immediately after I hit "send", it occurred to me that if StreamWriter
was defaulting to UTF8 output, then it probably *should* write the
identifier. So maybe that isn't a bug at all. But should it really be
writing it with every string, or should it just appear once at the top
of the file? Currently, the identifier is inserted once for every call
to Write(), and twice for every WriteLine(). I don't know what the spec
says but that doesn't seem right.

Jason
379