Fix freezing on Android when rotating

Fixes #1941

include/mbgl/map/map.hpp

@@ -58,6 +58,7 @@ public:
 
     // Pauses the render thread. The render thread will stop running but will not be terminated and will not lose state until resumed.
     void pause();
+    bool isPaused();
 
     // Resumes a paused render thread
     void resume();