A20plus data update

[noahm]

Big upgrades to the existing A20plus scraping data script:

• can now merge updated data into existing data file instead of wiping out custom flags, search terms, etc
• pulls data from both ZiV and ScoreAttack and merges to get the best of both
• scripts to pull jacket images for anything missing from remywiki (may also augment with ZiV simfiles jackets in the future)

All the above updates are now applied to our data file along with a bunch of manual updates to flags on songs marking unlockable songs, formerly unlockable songs, Japan-only songs, golden league, etc.