RKOrderedDictionary NSInvalidArgumentException

It happens from [`[RKOrderedDictionary dictionary]`] (https://github.com/CyberAgent/iOS-NBUImagePicker/blob/master/Source/Camera/NBUCameraView.m#L559) that passes 0 to `[RKOrderedDictionary initWithCapacity:]` at [RKOrderedDictionary.m line 55](https://github.com/CyberAgent/iOS-NBUKit/blob/master/Library/RestKit%20Support/RKOrderedDictionary.m#L55).

This causes a runtime error on devices, but works fine on the simulator.

> *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSMutableDictionary initWithCapacity:]: method only defined for abstract class.  Define -[RKOrderedDictionary initWithCapacity:]!'

I didn't encounter the warning mentioned at https://github.com/CyberAgent/iOS-NBUKit/commit/41a54100a69bb6635384c95421b358e79a1412d8. Could it possibly use `self = [super init]` instead?