Audit base game data

Following conclusion of Async III IV V:

• Update base game items to include any added during the course of the async
• Add game definitions for new games added to AP since v0.3.5
• Audit default priorities assigned - assuming a glitchless playthrough of whatever passes for a standard or default seed for a game:
  • high: key item/progression that is necessary for completion, or unlocks other item checks
  • medium: nice-to-have, but not strictly necessary
  • default: neutral
  • low: borderline (or actually) insulting to receive
• Add README documenting above rules

#31 may provide alternate sets of rules, keyed to common groups of settings for different seeds.