Enable refreshrate.avoid_25hz_30hz by default

There's no real reason to prefer 25hz over 50hz, or 30hz over 60hz,
ever. One might argue that motion interpolation could benefit from this,
but that's a bit pointless if the refresh rate is an integer multiple of
the video rate. If you really want that, just disable the option.

resources/settings/settings_description.json

@@ -246,7 +246,7 @@
       },
       {
         "value": "refreshrate.avoid_25hz_30hz",
-        "default": false,
+        "default": true,
         "hidden": true
       },
       {