Stop tracks before closing stream.

Otherwise the camera status light stays on.

static/sfu.js

@@ -54,6 +54,12 @@ Connection.prototype.close = function(sendit) {
     while(this.timers.length > 0)
         clearInterval(this.timers.pop());
 
+    this.stream.getTracks().forEach(t => {
+        try {
+            t.stop();
+        } catch(e) {
+        }
+    });
     this.pc.close();
 
     if(sendit) {