Fix poorly named function in RTCPeerConnection

CreateOffer -> CreateAnswer currently `pion-WebRTC` can only generate
offers not answers.

examples/gstreamer-receive/main.go

@@ -55,7 +55,7 @@ func main() {
 	}
 
 	// Sets the LocalDescription, and starts our UDP listeners
-	if err := peerConnection.CreateOffer(); err != nil {
+	if err := peerConnection.CreateAnswer(); err != nil {
 		panic(err)
 	}
 

examples/gstreamer-send/main.go

@@ -48,7 +48,7 @@ func main() {
 	}
 
 	// Sets the LocalDescription, and starts our UDP listeners
-	if err := peerConnection.CreateOffer(); err != nil {
+	if err := peerConnection.CreateAnswer(); err != nil {
 		panic(err)
 	}
 

examples/save-to-disk/main.go

@@ -57,7 +57,7 @@ func main() {
 	}
 
 	// Sets the LocalDescription, and starts our UDP listeners
-	if err := peerConnection.CreateOffer(); err != nil {
+	if err := peerConnection.CreateAnswer(); err != nil {
 		panic(err)
 	}
 

rtcpeerconnection.go

@@ -83,9 +83,12 @@ func (r *RTCPeerConnection) SetRemoteDescription(rawSessionDescription string) e
 }
 
 // CreateOffer starts the RTCPeerConnection and generates the localDescription
-// The order of CreateOffer/SetRemoteDescription determines if we are the offerer or the answerer
-// Once the RemoteDescription has been set network activity will start
 func (r *RTCPeerConnection) CreateOffer() error {
+	return errors.Errorf("CreateOffer is not implemented")
+}
+
+// CreateAnswer starts the RTCPeerConnection and generates the localDescription
+func (r *RTCPeerConnection) CreateAnswer() error {
 	if r.tlscfg != nil {
 		return errors.Errorf("tlscfg is already defined, CreateOffer can only be called once")
 	}