Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/CoreBluetooth/README.markdown

@@ -0,0 +1,38 @@
+# DEPRECATED
+
+THe promises provided here are not-sensible. You should use a full delegate pattern for CoreBluetooth, one shot listening for connectivity is not wise since the accessory may disconnect at any time.
+
+# PromiseKit CoreBluetooth Extensions ![Build Status]
+
+This project adds promises to Apple’s CoreBluetooth framework.
+
+## CocoaPods
+
+```ruby
+pod "PromiseKit/CoreBluetooth" ~> 6.0
+```
+
+The extensions are built into `PromiseKit.framework` thus nothing else is needed.
+
+## Carthage
+
+```ruby
+github "PromiseKit/CoreBluetooth" ~> 3.0
+```
+
+The extensions are built into their own framework:
+
+```swift
+// swift
+import PromiseKit
+import PMKCoreBluetooth
+```
+
+```objc
+// objc
+@import PromiseKit;
+@import PMKCoreBluetooth;
+```
+
+
+[Build Status]: https://travis-ci.org/PromiseKit/CoreBluetooth.svg?branch=master