Update MultiImageSelectorFragment.java

When select some pics in floder "all",and then switch to other floder,the selection will not change state right.This fixed it.(在“所有照片”文件夹中选择几张照片，然后切换到其它包含刚才选中的照片的文件夹中，选中状态没有正确显示。)

multi-image-selector/src/main/java/me/nereo/multi_image_selector/MultiImageSelectorFragment.java

@@ -299,6 +299,10 @@ public class MultiImageSelectorFragment extends Fragment {
                             if (null != folder) {
                                 mImageAdapter.setData(folder.images);
                                 mCategoryText.setText(folder.name);
+                                // 设定默认选择
+                                if (resultList != null && resultList.size() > 0) {
+                                    mImageAdapter.setDefaultSelected(resultList);
+                                }
                             }
                             mImageAdapter.setShowCamera(false);
                         }