Improve click detectors

Introduce "gadgets" as a structural function, for items that can be used
when held and when not held. Click detectors are such an item. Make
click detectors correctly attach and use up batteries when used.

src/Dodge/Default/Item.hs

@@ -38,7 +38,7 @@ singleAmmo x = IM.insert 0 x mempty
 defaultBulletWeapon :: Item
 defaultBulletWeapon = defaultHeldItem
         & itAmmoSlots .~ singleAmmo BulletAmmo
-        & itUse . heldAim . aimMuzzles .~ [Muzzle (V2 15 0) 0 0.01 0 PistolFlare MuzzleShootBullet]
+        & itUse . heldAim . aimMuzzles .~ [Muzzle (V2 15 0) 0 0.01 0 PistolFlare MuzzleShootBullet (UseExactly 1)]
 
 defaultConsumable :: Item
 defaultConsumable = defaultHeldItem & itUse .~ UseConsume CDoNothing

src/Dodge/Default/Item/Use/AimParams.hs

@@ -23,6 +23,7 @@ defaultAimParams =
                 , _mzAmmoSlot = 0
                 , _mzFlareType = DefaultFlareType
                 , _mzEffect = MuzzleShootBullet
+                , _mzAmmoPerShot = UseExactly 1
                 }
             ]
         }