修复内部不初始化selectedAssets导致外部未设置selectedAsset时序号始终为1的bug

TZImagePickerController/TZImagePickerController/TZImagePickerController.m

@@ -162,7 +162,7 @@
     if (self) {
         self.maxImagesCount = maxImagesCount > 0 ? maxImagesCount : 9; // Default is 9 / 默认最大可选9张图片
         self.pickerDelegate = delegate;
-        self.selectedModels = [NSMutableArray array];
+        self.selectedAssets = [NSMutableArray array];
         
         // Allow user picking original photo and video, you also can set No after this method
         // 默认准许用户选择原图和视频, 你也可以在这个方法后置为NO