v5.0.0

Version 5, the FFmpeg version

Completely changes dependency on mkvmerge, or MKVToolNix, to FFmpeg.

Important changes:

• mkvmerge_path is no longer a parameter to eztrim.
• audio_file must now actually be an audio file, and not a container.
• Always respects input filename extension when encoding with FFmpeg.
  • If audio_file='/path/to/afile.opus', the output will automatically become /path/to/afile_cut.opus.
  • If outfile='/path/to/different.wav', the output file extension will be overwritten with the audio_file extension, so this would output a cut/trimmed audio file a /path/to/different.opus.