Update to latest Swift version

[sidan5]

Currently this code is unusable...

Thanks!

[thomaspaulmann]

@sidan5 feel free to port it to the latest Swift version.

[miran248]

Got it working with few tweaks.

1. add the following to Heart Control WatchKit Extension/Info.plist

	<key>NSHealthShareUsageDescription</key>
	<string>We need access to your health data to read your heart rate.</string>
	<key>NSHealthUpdateUsageDescription</key>
	<string>We need to save your health progress to your Apple Watch.</string>

2. change the Swift Language Version to Swift 4 (Build Settings/Swift Compiler - Language section)
3. click fix on all suggestions
4. add @escaping on line 13 in Heart Control WatchKit Extension/AuthorizationManager.swift

static func requestAuthorization(completionHandler: @escaping ((_ success: Bool) -> Void)) {