Add DEFAULT category to Pico TTS service

Change-Id: I4d94d41d3e5e9d9bd2b266ac4637c065ef13810a
diff --git a/pico/AndroidManifest.xml b/pico/AndroidManifest.xml
index 077c17f..b5ffe45 100755
--- a/pico/AndroidManifest.xml
+++ b/pico/AndroidManifest.xml
@@ -22,6 +22,7 @@
                   android:label="@string/app_name">
             <intent-filter>
                 <action android:name="android.intent.action.TTS_SERVICE" />
+                <category android:name="android.intent.category.DEFAULT" />
             </intent-filter>
         </service>