* [Feature] Add tool to show origin or augmented train data

* [Feature] Support eval concate dataset

* Add docstring and modify evaluate of concate dataset

Signed-off-by: FreyWang <wangwxyz@qq.com>

* format concat dataset in subfolder of imgfile_prefix

Signed-off-by: FreyWang <wangwxyz@qq.com>

* add unittest of concate dataset

Signed-off-by: FreyWang <wangwxyz@qq.com>

* update unittest for eval dataset with CLASSES is None

Signed-off-by: FreyWang <wangwxyz@qq.com>

* [FIX] bug of generator,  which lead metric to nan when pre_eval=False

Signed-off-by: FreyWang <wangwxyz@qq.com>

* format code

Signed-off-by: FreyWang <wangwxyz@qq.com>

* add more unittest

* add more unittest

* optim concat dataset builder