Add optional debug log switch

Summary:
This won't affect runtime, but is useful when debugging issues with flipper itself.
Setting this flag means all state changes will be output in logcat.

Reviewed By: passy

Differential Revision: D10231148

fbshipit-source-id: 7ddd490290ad973fc339b2f5f93a6f9a1fab4577

xplat/Flipper/FlipperState.h

@@ -52,7 +52,7 @@ class FlipperState {
   void started(std::string);
 
   std::shared_ptr<FlipperStateUpdateListener> mListener = nullptr;
-  std::string log;
+  std::string logs;
   std::vector<std::string> insertOrder;
   std::map<std::string, facebook::flipper::State> stateMap;
 };