Fix gstreamer-send for Firefox temporarily

Alter the transceiver direction to sendrecv to satisfy Firefox.

Author: mchlrhw

README.md

@@ -53,6 +53,7 @@ Check out the **[contributing wiki](https://github.com/pion/webrtc/wiki/Contribu
 * [Simonacca Fotokite](https://github.com/simonacca-fotokite)
 * [Steve Denman](https://github.com/stevedenman)
 * [RunningMan](https://github.com/xsbchen)
+* [mchlrhw](https://github.com/mchlrhw)
 
 ### License
 MIT License - see [LICENSE](LICENSE) for full text

gstreamer-send/jsfiddle/demo.js

@@ -28,9 +28,9 @@ pc.onicecandidate = event => {
 }
 
 // Offer to receive 1 audio, and 2 video tracks
-pc.addTransceiver('audio', {'direction': 'recvonly'})
-pc.addTransceiver('video', {'direction': 'recvonly'})
-pc.addTransceiver('video', {'direction': 'recvonly'})
+pc.addTransceiver('audio', {'direction': 'sendrecv'})
+pc.addTransceiver('video', {'direction': 'sendrecv'})
+pc.addTransceiver('video', {'direction': 'sendrecv'})
 pc.createOffer().then(d => pc.setLocalDescription(d)).catch(log)
 
 window.startSession = () => {