persist actual data to disk rather than just names

[ywwg]

right now we're not actually persisting the counts to disk, we're cheating. POST FIREFLY AND NOT BEFORE, I should fix this.

• serialize and deserialize to csv should be funcs on the Item interface: "ItemType, [param0], [param[1]"...
• create a lookup func that switches on itemtype string to a constructor. Constructor takes CSV, converts to what the constructor actually wants.
• when loading, call the lookup func with ItemType string and pass the remaining csv params, get back the actual item we want