Issue70 profile names2

I just rewrote this. 
I think this need to be a bit different. RTP/AVP is only accepted if their is a a=fingerprint line. If the browser get's a offer with RTP/AVP and no fingerprint and starts sending it DTLS, that is not OK. I realize that you argue this would not happen because the offer would later be rejected because there is no fingerprint line so the net result is the same but I think the text here is the wrong way to phrase it.