core (Cagou): add debug log for widget visibility + ignore_missing: - debug log are now use to show which widget are made (in)visible, and to show the list of currently visible widgets - "ignore_missing" can be used in _removeVisibleWidget when we can expect that a widget is missing in visible widgets list.

<intent-filter>
    <action android:name="android.intent.action.SEND" />
    <category android:name="android.intent.category.DEFAULT" />
    <data android:mimeType="*/*" />
</intent-filter>