Fixing tests for UserData-related functionality

Conflicts:
	countly-sdk-android/AndroidManifest.xml
	countly-sdk-android/tests/AndroidManifest.xml
Adding Advertising ID support

Conflicts:
	countly-android-example/src/ly/count/android/example/CountlyActivity.java
	countly-sdk-android-messaging/src/ly/count/android/api/messaging/CountlyMessaging.java
	countly-sdk-android/src/ly/count/android/api/Countly.java
	countly-sdk-android/src/ly/count/android/api/MessagingAdapter.java
Advertising ID support

Conflicts:
	README.md
	countly-android-example/src/ly/count/android/example/CountlyActivity.java
	countly-sdk-android-messaging/src/ly/count/android/api/messaging/CountlyMessaging.java
	countly-sdk-android/src/ly/count/android/api/MessagingAdapter.java