Enable refresh receipt on macOS

Details here: #127

Groundwork to enable 3rd party receipt validation

• Define ReceiptValidator protocol and default AppleReceiptValidator implementation
• This is passed to SwiftyStoreKit.verifyReceipt() as follows (API breaking change):

let appleValidator = AppleReceiptValidator(service: .production)
SwiftyStoreKit.verifyReceipt(using: appleValidator, password: "your-shared-secret") { result in
     // handle result
}     

See #126 for additional reference.

Fix for non-atomic completion in completeTransactions()

0.6.1

Pod version 0.6.1

Add Non-Atomic Purchases

For cases when the host app needs to unlock functionality stored on a server as part of an in-app purchase, SwiftyStoreKit now enables non-atomic purchases.

This is an API breaking change. See the README for example usages.

This fixes #96 and #50.

Rename targets and schemes

What is this

Improved name consistency for targets and schemes in the project. Usage is the same - no API changes.

SwiftyStoreKit now has three framework targets and two demo app targets:

• SwiftyStoreKit_iOS
• SwiftyStoreKit_macOS
• SwiftyStoreKit_tvOS
• SwiftyStoreKit_iOSDemo
• SwiftyStoreKit_macOSDemo

The schemes have also been renamed to follow a similar convention.

See related issue: #62

Expose local receipt data from Bundle

The local receipt data can now be read like so:

let receiptData = SwiftyStoreKit.localReceiptData
let receiptString = receiptData.base64EncodedString
// do your receipt validation here

This can be used to perform local receipt validation (not implemented yet, see #101)

SKProduct+LocalizedPrice

• Add SKProduct extension to provide a localized price
• Update in app receipt URL type enum to Swift 3 naming convention
• Update README and sample demos to provide a password when calling verifyReceipt()

Fix for verifySubscription

• This release fixes #68 by using the receipt request date when checking if a subscription is expired.

Final Swift 2.3 Release

0.4.0

Updated README with Swift 2.3 support

Initial Swift 3.0 Release

0.5.0

Update versioning info on README