* Add anchor generator operator for Faster-RCNN.
* Add unittest testing.
* Add Python API.

This reverts commit bc28cf61.

* Fix mean iou op.

* Fix crop layer test.

* Fix unitest

* fix unitest.

* Add fill_zeros_array op. This op is used for zero-filling an LoDTensorArray.

* merge fill_zeros_array_op with fill_zeros_like_op

* add unit_test for fill_zeros_like for array

* bnorm+relu fuse for mkldnn

* separate fuse_relu function

* bug fix

* proper while range in inference_transpiler

* description fix

* review fix

* review fix

* unit test for fwd batch norm+relu MKLDNN fuse

* Speed depthwise transposed conv2d.

* Fix relu and log

* Update nn.py

This reverts commit 4d8e8ee2, reversing
changes made to d6a9f005.

1. Add a new attribute named 'startuo_seed' to RandomCropOp. If the input
'Seed' is not initialized, the 'startup_seed' will be used to replace
it.

2. Refine CustomReader. Add a member variable 'scope_' to it. The
'scope_' will act as the global scope of preprocesing, making it
possiable to save something cross batches.

* "add some api reference"

* "fix based on preview"

* "fix evaluator"

* "remove template doc"

* "add some api reference"

* "fix based on preview"

* "fix evaluator"

* "remove template doc"

Give assign layer's second parameter 'output' a default value: None. If
it is None, the output variable will be created inside the layer.