Improve music metadata

[biggeryetbetter]

Included in this PR are a number of recordkeeping changes that will enhance the info accessible about in-game music.
This includes:

• Addition of most missing author and license information (with the exception of two retro tracks)
• Addition of barebones titles (some are very bland - composers should go through and add their own if they want)
• Versions and remixes of tracks are clearly and consistently denoted.
• Some titles were revised (e.g. for typos, "Crystal Cave + Mysterious Ambience" to the usual title "Jewels")
• Embedding of all metadata into the audio files. This makes it easy to manage with outside music players. Looping metadata may be hit or miss due to no standard format.
• Music section in AUTHORS is alphabetically sorted, revised, and updated.