* Add head bbox for Pyramid-Box model.

* Fix bug in transform_labels and satisfy_sample_constraint function.

* Add object_coverage constraint & fix bbox_labels data layout bug

* code clean

* Support groups in de-conv and fix bug.

* Clean code.

* Fix model config.

* Some mirror changes in data argumentations.

* Set learning rate by input arguments.

* Support groups in de-conv and fix bug.

* Clean code.

* training code of pyramidbox

* Fix code format.

* load pretrained vgg model

* load pretrained vgg model

* delete irrelevant tools

* delete unused lines

* PyramidBox for face detection.

* Update some hyper parameters.

* Update pyramidbox.py