Added calculateFileSize.
Added calculateFileSize.

jpipard/DKImagePickerController,metasmile/DKImagePickerController,zhangao0086/DKImagePickerController,zhangao0086/DKImagePickerController,North-American-Signs/DKImagePickerController,metasmile/DKImagePickerController,gorjuspixels/DKImagePickerController,gorjuspixels/DKImagePickerController,North-American-Signs/DKImagePickerController,jpipard/DKImagePickerController