Basic integration of Crashlytics for iOS... #549 (added Android as well)

Author: EddyVerbruggen

docs/CRASHREPORTING.md

@@ -1,14 +1,5 @@
 <img src="https://raw.githubusercontent.com/EddyVerbruggen/nativescript-plugin-firebase/master/docs/images/features/crash.png" height="85px" alt="Crash Reporting"/>
 
 ## Enabling Crash Reporting
-With plugin version 3.9.0+ you will be prompted during installation of the plugin to enable Crash Reporting (it's off by default).
-
-In older versions it was on by default but it may slow down app startup a bit so now it's disabled by default.
-
-## Making sense of the stacktraces
-Please read [the official docs](https://firebase.google.com/docs/crash/)
-on what Crash reporting is and what you can do to have a better experience.
-
-## Future work
-There's an option to send logs to Firebase along with the crash in order
-to add some context. This is however currently problematic on iOS but we'll keep an eye out.
+Since version 5.3.0 you can choose either Crashlytics (recommended) or the older Firebase crash reporting (which doesn't really work on iOS).
+You will be prompted during installation of the plugin to enable either Crashlytics or Crash Reporting (it's off by default).