[formatsort] Remove misuse of 'preference'

'preference' is to be used only when the format is better that ALL qualities of a lower preference irrespective of ANY sorting order the user requests. See deezer.py for correct use of this

In the older sorting method, `preference`, `quality` and `language_preference` were functionally almost equivalent. So these disparities doesn't really matter there

Also, despite what the documentation says, the default for `preference` was actually 0 and not -1. I have tried to correct this and also account for it when converting `preference` to `quality`

youtube_dlc/extractor/vidme.py

@@ -181,6 +181,7 @@ class VidmeIE(InfoExtractor):
                     'url': format_url,
                     'width': int_or_none(f.get('width')),
                     'height': int_or_none(f.get('height')),
+                    # Clips should never be prefered over full video
                     'preference': 0 if f.get('type', '').endswith(
                         'clip') else 1,
                 })