Update Crashlytics to 2.9.1, Fabric plugin to 1.25.2.
Update Crashlytics to 2.9.1, Fabric plugin to 1.25.2.

- Crashlytics: startup time improvement.
- Fabric: Fixed “registerResGeneratingTask” deprecation warning.

UweTrottmann/SeriesGuide,UweTrottmann/SeriesGuide