Restructure user notifications.

static/sfu.js

@@ -678,7 +678,7 @@ function serverConnect() {
                 gotPermissions(m.permissions);
                 break;
             case 'user':
-                gotUser(m.id, m.username, m.del);
+                gotUser(m.id, m.kind, m.username);
                 break;
             case 'chat':
                 addToChatbox(m.id, m.username, m.kind, m.value);
@@ -900,11 +900,18 @@ function resetUsers() {
         delUser(id, users[id]);
 }
 
-function gotUser(id, name, del) {
-    if(del)
-        delUser(id, name);
-    else
+function gotUser(id, kind, name) {
+    switch(kind) {
+    case 'add':
         addUser(id, name);
+        break;
+    case 'delete':
+        delUser(id, name);
+        break;
+    default:
+        console.warn('Unknown user kind', kind);
+        break;
+    }
 }
 
 function displayUsername() {

webclient.go

@@ -112,11 +112,15 @@ func (c *webClient) Credentials() clientCredentials {
 }
 
 func (c *webClient) pushClient(id, username string, add bool) error {
+	kind := "add"
+	if !add {
+		kind = "delete"
+	}
 	return c.write(clientMessage{
 		Type:     "user",
+		Kind:     kind,
 		Id:       id,
 		Username: username,
-		Del:      !add,
 	})
 }
 
@@ -181,7 +185,6 @@ type clientMessage struct {
 	Candidate   *webrtc.ICECandidateInit   `json:"candidate,omitempty"`
 	Renegotiate bool                       `json:"renegotiate,omitempty"`
 	Labels      map[string]string          `json:"labels,omitempty"`
-	Del         bool                       `json:"del,omitempty"`
 	Request     rateMap                    `json:"request,omitempty"`
 }