Implement modular weapons.

- 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.

common/src/states/utils.rs

@@ -294,14 +294,14 @@ pub fn handle_wield(data: &JoinData, update: &mut StateUpdate) {
 
 /// If a tool is equipped, goes into Equipping state, otherwise goes to Idle
 pub fn attempt_wield(data: &JoinData, update: &mut StateUpdate) {
-    if let Some(ItemKind::Tool(tool)) = data
+    if let Some((item, ItemKind::Tool(tool))) = data
         .inventory
         .equipped(EquipSlot::Mainhand)
-        .map(|i| i.kind())
+        .map(|i| (i, i.kind()))
     {
         update.character = CharacterState::Equipping(equipping::Data {
             static_data: equipping::StaticData {
-                buildup_duration: tool.equip_time(),
+                buildup_duration: tool.equip_time(item.components()),
             },
             timer: Duration::default(),
         });