Both Android and iOS now use pause/resume. The map thread is
always running, and be able to receive messages. When paused,
it will just refuse to render.
- static rendering now also runs in a separate thread; you have to start it with map.start(Map::Mode::Static) and join the thread with map.stop() before destructing the Map object
- map.renderStill() takes a callback with will be invoked on the *map* thread, so you'll have to figure out your own method of dispatching back to the main thread.
Now the FixtureLog is an Log::Observer instead of a backend. The
observer can sniff and filter log messages, that can be used
for fail a test if it emits a warning for example.
