mpd: Update type converters naming and add UINT

Also adds tests for RANGE helper.
mpd: Convert channels and stickers and delete empty.
mpd: Update auth filter and convert audio_output and connection
mpd: Stop string escaping all input as we have a proper tokenizer
mpd: Convert command lists and stored playlists
mpd: Convert reflection and mark non listed commands
mpd: Implement playlistinfo from current playlist
mpd: Convert non-search bits of music db
mpd: Convert search functions in music db
mpd: Complete music db conversion with list
mpd: Remove old command handlers