Update CHANGES.

CHANGES

 Galène 0.4 (unreleased):
 
   * Implemented simulcast.
-  * Implemented scalable video coding (SVC) for VP8.
-  * Fixed the profile announced for VP9.
+  * Implemented scalable video coding (SVC) for VP8 and VP9.
   * Preliminary support for the AV1 codec.
-  * Simplified the protocol by labelling streams rather than individual
-    tracks.
+  * Fixed the profile announced for VP9.
+  * Reworked the disk writer, which should no longer cause corruption
+    after packet loss.
+  * 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.
+  * 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