minor changes to server-sent events
minor changes to server-sent events

Change yaws_sse to send close connection header by default, and change the
example to return an Allow header if anything other than GET is requested.

jgrinstead/yaws,jgrinstead/yaws,jgrinstead/yaws,jgrinstead/yaws,jgrinstead/yaws,jgrinstead/yaws,jgrinstead/yaws