- rename "Invite Room" node to "Invite to Room" to distinguish from new node

- new node "Invite Room" for receiving room invites
- new node "Leave Room" for leaving a room
- updated examples with new nodes

src/matrix-invite-room.html

@@ -12,9 +12,9 @@
             roomId: { value: null },
         },
         label: function() {
-            return this.name || "Room Invite";
+            return this.name || "Invite to Room";
         },
-        paletteLabel: 'Room Invite'
+        paletteLabel: 'Invite to Room'
     });
 </script>