- Add ItemKind::ModularComponent, Item::components.
- Add tool::StatKind::{Direct,Modular} for the modular weapons themselves.
- Move ItemConfig from ItemDesc to Item, so components' stats can be taken into account.
- Crafting stores into the components field.
- Components/recipes/placeholders are created dynamically.
- Show which components a modular weapon contains in the tooltip in voxygen.
Squashed fixes:
- `Item::duplicate` components in `Item::new_from_item_def`.
- Speed of 1.0 for now.