Bugfix: State restoration for mock

[philips77]

This PR fixes the Central Manager state restoration for mock central manager.

I acually tried starte restoration using a native API and did my best to repliacte the same behavior using mock implementation.

Changes

• State restoration requires the app to have "Background Mode": bluetooth-central - this was added to nRF Blinky sample app.
• The Central Manager in nRF Blinku is created using an identifier:
  

  IOS-CoreBluetooth-Mock/Example/nRFBlinky/Models/BlinkyManager.swift

  Lines 50 to 58 in 2991245

  	centralManager = CBCentralManagerFactory.instance(
  	delegate: self,
  	queue: nil,
  	options: [
  	CBCentralManagerOptionShowPowerAlertKey : true,
  	CBCentralManagerOptionRestoreIdentifierKey : "no.nordicsemi.blinky"
  	],
  	forceMock: mock
  	)

• This will cause the CBCentralManagerDelegate report centralManager(_:willRestoreState:) just after it has been initiated, before its state changes to .poweredOn.
• The reported restored state consists of 3 items:
  • Previously connected peripherals (as an array of CBMPeripheral in this library)
  • Previously used llist of Service UUID filters, when the app was killed during scanning and filter was set
  • Previously used scan options, when the app was killed during scanning and any option was set
• To mock this behavior the CBMCentralManagerMock has a static property simulateStateRestoration. An example, how it can be used is in AppDelegate:
  

  IOS-CoreBluetooth-Mock/Example/nRFBlinky/AppDelegate.swift

  Lines 67 to 82 in 2991245

  	// Simulate state restoration.
  	CBMCentralManagerMock.simulateStateRestoration = { identifierKey in
  	if identifierKey == "no.nordicsemi.blinky" {
  	return [
  	// When the app was killed it was scanning with the LBS Service UUID filter.
  	CBMCentralManagerRestoredStateScanServicesKey: [CBMUUID.nordicBlinkyService],
  	// Also, the app was scanning with the "Allow Duplicates" option enabled.
  	CBMCentralManagerRestoredStateScanOptionsKey: [CBMCentralManagerScanOptionAllowDuplicatesKey: true as NSNumber],
  	// nRF Blinky was already connected. Check out, that the
  	// blinky spec was created using .connected(...) and it is
  	// in range.
  	CBMCentralManagerRestoredStatePeripheralsKey: [blinky]
  	]
  	}
  	return nil
  	}

  
  Note, that the CBMCentralManagerRestoredStatePeripheralsKey key allows to set CBMPeripheralSpec to be returned to the delegate.
• The returned CBMPeripheral will be in stae .connected, or .connecting, depending on whether the device is in range, or not. Non-connectable peripheral specs are ignored.