updated changelog

changes

@@ -2,10 +2,13 @@
      - exam melodies from melody set can be played in order
      - melodies order in set is editable
      - user can define repeats number of melodies from the set
-     - updated SoundTouch library version to 2.2 (Windows&Android)
+     - improved level preview table
+     - updated SoundTouch library version to 2.2 (Windows, Android)
     ANDROID
      - display menu entries to navigate exam (along with quick buttons)
      - indicate input volume by scaling menu button dot
+    LINUX
+     - fixed AppImage issues - works under Wayland as well
 
 1.7.2 beta2
      - improved rhythm detection