Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/StoreKit/Sources/SKRequest+AnyPromise.m

@@ -0,0 +1,48 @@
+//
+//  PromiseKit+StoreKit.m
+//  Aluxoft SCP
+//
+//  Created by Josejulio Martínez on 16/05/14.
+//
+
+#import "SKRequest+AnyPromise.h"
+#import <StoreKit/SKProductsRequest.h>
+
+//TODO do categories work on inherited classes? As would solve our swift SKProductsRequest problem
+
+@interface PMKSKRequestDelegate : NSObject <SKProductsRequestDelegate> {
+@public
+    PMKResolver resolve;
+    id retainCycle;
+}
+@end
+
+@implementation PMKSKRequestDelegate
+
+- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response {
+    resolve(response);
+    retainCycle = request.delegate = nil;
+}
+
+- (void)requestDidFinish:(SKRequest *)request {
+    resolve(nil);
+    retainCycle = request.delegate = nil;
+}
+
+- (void)request:(SKRequest *)request didFailWithError:(NSError *)error {
+    resolve(error);
+    retainCycle = request.delegate = nil;
+}
+
+@end
+
+@implementation SKProductsRequest (PromiseKit)
+
+- (AnyPromise *)promise {
+    PMKSKRequestDelegate *d = [PMKSKRequestDelegate new];
+    d->retainCycle = self.delegate = d;
+    [self start];
+    return [[AnyPromise alloc] initWithResolver:&d->resolve];
+}
+
+@end