New API with class method allowing to bypass some behaviours if no RMResourceManager singleton has been set.
New API with block:

+ (NSString *)pathForResource:(NSString *)name ofType:(NSString *)ext observer:(id)observer usingBlock:(void(^)(id observer, NSString* path))updateBlock

+ (UIImage*)imageNamed:(NSString *)name update:(void(^)(UIImage* image))update;
+ (UIImage*)imageWithContentsOfFile:(NSString *)path update:(void(^)(UIImage* image))update;