Update CHANGES for 0.4.

CHANGES

-Galène 0.4 (unreleased):
+5 September 2021: Galène 0.4
 
   * Implemented simulcast.
   * Implemented scalable video coding (SVC) for VP8 and VP9.
@@ -7,20 +7,18 @@ Galène 0.4 (unreleased):
   * Reworked the disk writer, which should no longer cause corruption
     after packet loss.
   * Added support for recording H.264 tracks.
-  * Added a close button to video windows, it is now possible to close
-    just a single shared window.
   * Reworked the signalling protocol, it is now possible to request
     different tracks for distinct streams, and there are provisions to
     carry user permissions and statuses; this is not yet used by the user
     interface.
-  * The server will now attempt to increase the file descriptor limit at
-    startup.
   * Reworked internal signalling; this will hopefully fix issues with
     losing tracks under load.
   * Added an option to limit the range of UDP ports used by the server.
   * Added a close button in every locally-generated video; this allows
-    closing individual screen shares and avoids the need for creating
-    buttons at the top.
+    closing individual screen shares and simplifies the UI by not creating
+    close buttons in the top bar.
+  * The server will now attempt to increase the file descriptor limit at
+    startup.
   * Stats are now exported as JSON and formatted on the client side; the
     stats URL is now /stats.html rather than just /stats.