Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/Photos/Tests/PHPhototLibraryTests.swift

@@ -0,0 +1,12 @@
+import PromiseKit
+import PMKPhotos
+import Photos
+import XCTest
+
+class PHTestCase: XCTestCase {
+    func test() {
+        let ex = expectation(description: "")
+        PHPhotoLibrary.requestAuthorization().done{ _ in ex.fulfill() }
+        waitForExpectations(timeout: 10)
+    }
+}