Compatibility breaking changes that should be done at some point

[fgenesis]

Should do these in one go.

• Windows: Use user directory instead of workdir #30
• Add mod compatibility scripts to game files #31
• Save world map exploration data in base64-encoded binary only
• Switch to Android-compatible Gem list in save file (see Continuity::saveFile()). Possibly autodetect the old format, since we want to stay forward compatible?
• Update online mod repo: Re-upload affected mods with scripts adjusted to work with the compatibility script from Add mod compatibility scripts to game files #31