Add support for Android's logging subsystem.
This patch adds support for Android's logging subsystem in Tor. When debugging Android applications it is useful to be able to collect information about the application running on the platform via the various system services that is available on the platform. This patch allows you to add "Log notice android" to your torrc and have Tor send everything above and including the notice severity to Android's ring buffer which can be inspected using the 'adb logcat' program. See: https://bugs.torproject.org/24362