Cargo manifest

[JensAyton]

In Oolite 1.x, the player’s cargo manifest is represented as a market property list (an array of arrays in the format of commodities.plist). The entire array is included in saved games.

Do we actually need anything there apart from commodity names and quantities? I’d like to use the obvious representation in saved games:
manifest:
{
Food: 15,
Narcotics: 3
}
…and a dictionary-based format for commodities.plist or whatever replaces it.