Besides removing unnecessary imports, this also fixes the missing logger module in test_architectures.py within the static directory.

add htc model 

* add server side rcnn model, 62 fps with coco mAP 41.6% and 20fps with coco mAP 47.8%

* add multi-scale testing function in cascade rcnn clsaware architecture

* exit1 in travis failed

* add softnms, nonlocal, resnet200_vd_backbone
* add CBNet
* update model zoo

* add multi-scale test

* add cascade gn

* add cascade mask gn config

* update configs

* refine cascade models

* Clean up a bit

* Add `__shared__` annotation for shared variables between modules

* Dedup `num_classes` configurations

* Document `__shared__` usage

* Remove some unused variable

* Improve docstring and add comments for `__shared__`

* Rename object_detection to PaddleDetection
* Small fix for doc