Better Format Sorting (Squashed)

* Added --format-sort (-S height,filesize)
* Made fields reversible (-S +height)
* Added --format-sort-force, --no-format-sort-force
* Added limit (-S height:720)
* Added codec preference (-S vcodec,acodec)
* Correct handling of preference<-1000

* Rebased to yt-dlc
* Automatically determine missing bitrates
* aext, vext, protocol, acodec, vcodec can now takes priority as string, not number (-S vext:webm)
* Correct handling of None in codec, audio_codec (None means the codec is unknown while 'none' means it doesn't exist)
* Correctly parse filesize (-S filesize:200M)
* Generalized preference calculation

* Rewrote entire code into the class FormatSort
* Correctly handle user input errors
* Combined fields (-S +ext:webm:webm)
* Closest mode (-S filesize~50M)
* Aliases (framerate=fps, br=bitrate etc)

* Documentation

youtube_dlc/__init__.py

@@ -8,6 +8,7 @@ __license__ = 'Public Domain'
 import codecs
 import io
 import os
+import re
 import random
 import sys
 
@@ -41,6 +42,7 @@ from .downloader import (
     FileDownloader,
 )
 from .extractor import gen_extractors, list_extractors
+from .extractor.common import InfoExtractor
 from .extractor.adobepass import MSO_INFO
 from .YoutubeDL import YoutubeDL
 
@@ -245,6 +247,9 @@ def _real_main(argv=None):
         parser.error('Cannot download a video and extract audio into the same'
                      ' file! Use "{0}.%(ext)s" instead of "{0}" as the output'
                      ' template'.format(outtmpl))
+    for f in opts.format_sort:
+        if re.match(InfoExtractor.FormatSort.regex, f) is None:
+            parser.error('invalid format sort string "%s" specified' % f)
 
     any_getting = opts.geturl or opts.gettitle or opts.getid or opts.getthumbnail or opts.getdescription or opts.getfilename or opts.getformat or opts.getduration or opts.dumpjson or opts.dump_single_json
     any_printing = opts.print_json
@@ -347,6 +352,8 @@ def _real_main(argv=None):
         'simulate': opts.simulate or any_getting,
         'skip_download': opts.skip_download,
         'format': opts.format,
+        'format_sort': opts.format_sort,
+        'format_sort_force': opts.format_sort_force,
         'listformats': opts.listformats,
         'outtmpl': outtmpl,
         'autonumber_size': opts.autonumber_size,