Add registration notification support.

AndroidManifest.xml

@@ -262,6 +262,13 @@
               android:grantUriPermissions="true"
               android:authorities="org.thoughtcrime.provider.securesms" />
 
+    <receiver android:name=".service.RegistrationNotifier"
+              android:exported="false">
+        <intent-filter>
+            <action android:name="org.thoughtcrime.securesms.REGISTRATION_EVENT" />
+        </intent-filter>
+    </receiver>
+
        <uses-library android:name="android.test.runner" />
 </application>