Version 3: Code restructure, fixes and a new menubar window

Thank you everyone for waiting through the summer for an update.

Fixes:

• Spotify lyrics fetching is fixed
• Complete restructuring of internal code. Fewer bugs and easy to extend in the future (I'm thinking of adding QQMusic support next release)
• Apple Music support added back! Not only can Apple Music users use Spotify lyrics, I also use Spotify song details (such as "Ame No Minuet" on Apple Music becoming "雨のメヌエット", helping us get accurate NetEase lyrics)
• The app goes through a list of lyric providers, so if one of them fails it tries fetching from the next one
• New manual search window where you can input a custom song name or artist name
• New menubar window view. easy to use buttons and a much better UI than before
• New AirPlay delay mode
• Can use sliders to adjust Spotify/Apple Music volume, as well as menubar size, as well as the Spotify connect delay time
• karaoke window doesn't display translation if multilingual setting is on and translation is a duplicate line