title: add my TTS Engine to Android TTS Serivce like SAPI
body: <p>I have developed my own TTS apps in Android. Is there any way to deploy my TTS engine into the OS instead on running the TTS apps, so that other apps can call my TTS? Something like SAPI in MS Window. SVOX can package the engine as apk and after installed, it adds new engines into the Andorid OS, not sure how can I do that same.</p>