Fixed things, Added macro for convenience, Changed for preprocessor FLURRY

- Fixed a crash bug if application did enter into background (cocos2d-x related)
- Added a macro wrapping up a frequent in use one of method `flurryLogEvent()`.
- Modified `flurryLogEvent()` to accept variable argument. More flexible to log event. This works with an added macro.
- Changed flurry related method calls to adhere to preprocessor FLURRY (either `#define FLURRY` or define it per project-based ie. XCode's Build Setting->Apple LLVM 6.0 - Preprocessor, for each target build).

Tested, and result was up in Flurry dashboard.