update all CocoaPods dependencies as part of the Xcode/iOS upgrade (#334, #335)
update all CocoaPods dependencies as part of the Xcode/iOS upgrade (#334, #335)

changes:
- CocoaLumberjack 3.4.2 -> 3.6.1 (latest version 3.6.1)
- Crashlytics 3.12.0 -> 3.14.0 (latest version 3.14.0)
- Fabric 1.9.0 -> 1.10.2 (latest version 1.10.2)
- Firebase 5.15.0 -> (unused) (latest version 6.16.0)
- FirebaseAnalytics 5.4.0 -> 6.2.2 (latest version 6.2.2)
- FirebaseCore 5.1.10 -> 6.6.1 (latest version 6.6.1)
- FirebaseInstanceID 3.3.0 -> 4.3.0 (latest version 4.3.0)
- GoogleAppMeasurement 5.4.0 -> 6.2.2 (latest version 6.2.2)
- GoogleUtilities 5.3.6 -> (unused) (latest version 6.5.1)
- MBProgressHUD 1.1.0 -> 1.2.0 (latest version 1.2.0)
- nanopb 0.3.901 -> 0.3.9011 (latest version 0.3.9011)

herzbube/littlego,herzbube/littlego,herzbube/littlego,herzbube/littlego,herzbube/littlego