Transmit response headers (response.data[3]?) w/ sendHeaders
When sendHeaders is called, it currently expects an HTTP response code, and a  PStringTable of headers; it would be nice if the response code defaulted to HTTP 200 OK, and there was an overload for "sendHeaders" that automatically sent up the built-up response headers (i.e. headers["content-type"] = "text/html") if the user does not provide a PStringTable.
