Iterate feature-based products

Passepartout-iOS/Global/Product.swift

@@ -97,6 +97,18 @@ enum Product: String {
     // MARK: All
 
     static let all: [Product] = allDonations + allFeatures + allProviders
+    
+    var isDonation: Bool {
+        return Product.allDonations.contains(self)
+    }
+
+    var isFeature: Bool {
+        return Product.allFeatures.contains(self)
+    }
+
+    var isProvider: Bool {
+        return Product.allProviders.contains(self)
+    }
 }
 
 extension Infrastructure.Name {

Passepartout-iOS/Global/ProductManager.swift

@@ -80,6 +80,21 @@ class ProductManager: NSObject {
         return inApp.product(withIdentifier: identifier)
     }
     
+    func featureProducts(includingFullVersion: Bool) -> [SKProduct] {
+        return inApp.products.filter {
+            guard let p = Product(rawValue: $0.productIdentifier) else {
+                return false
+            }
+            guard includingFullVersion || p != .fullVersion else {
+                return false
+            }
+            guard p.isFeature else {
+                return false
+            }
+            return true
+        }
+    }
+    
     func purchase(_ product: SKProduct, completionHandler: @escaping (InAppPurchaseResult, Error?) -> Void) {
         inApp.purchase(product: product) {
             if $0 == .success {