Forward null window id to Java AndroidPlatformHelper so it can remove the SurfaceListener that can cause setNativeVideoWindowId to be called when there is no Core

Started init/start/uninit process refactor to add a stop() method to be able to destroy a Core in a more deterministic way than in the destructor

If net_auto_state_mon is activated then the network would be reachable only if
both of network_reachable and network_reachable_internal are set to TRUE.
If not only network_reachable will be used.