* add is_test to pooling and activations

add prop_kind support for layers activation. conv and pooling

add a pass that sets is_test to true

add transpiler version of is_test pass

test=develop

* patch test and pass

test=develop

* add pass to analyzer.h

test=develop

* add is_test attr description & pass only on mkldnn

in:
activation_op.cc
batch_norm_op.cc
conv_op.cc
dropout_op.cc
lrn_op.cc
pool_op.cc
sequence_pool_op.cc
softmax_op.cc

* fix is_test handling for activation pool and conv

* change description of is_test for all layers again

* remove GetAttr(use_mkldnn) from pass

* rename correct_mkldnn_test_phase to is_test

and remove dependency on MKLDNN
test=develop

* review fix magic number

* two if(..)s into one

* Check is_test once and pass mkldnn forward prop kind

* dereference shared_ptr with * (without get())

test=develop

* add is_test_pass back

test=develop

* add selu

* use for range
test=develop

* add API
test=develop

* follow comment
test=develop

* update API.spec
test=develop

test=develop

* fix test_save_load with pickle

test=develop

* fix test_save_load with pickle

test=develop

* fix test_save_load with pickle

test=develop

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* Support softmax return in softmax_with_cross_entropy

* Add test for return_softmax=False

test=develop

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Density prior box operator for image detection model.

test=develop

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* add lod tensor array concat

* add lod tensor array concat

* test=develop

* add lod tensor array concat
test=develop

* Fix API.spec
test=develop

* add lod tensor array concat
test=develop

* revise some bug of lod tensor array concat
test=develop

* add unittest for tensor array concat
test=develop

* change to tensor array to tensor
test=develop

* revise bug
test=develop

* revise a bug
test=develop

* revise a bug
test=develop

* revise a bug of python3
test=develop

* exhaustive search for cuDNN conv.
* Refine code and add unit testing.
* Fix model load in fluid/inference and unit testing in conv2d
* Follow comments.
* Fix compiling test=develop

test=develop

the build strategy is finalized after create_passes. So future
change of build strategy has no effects.

test=develop

test=develop

* fix input<tensor>
test=develop

* fix split_ids
test=develop

* ElementwiseMul should not support SelectedRows

* fix scale op
test=develop

* change GetTensorFromVar() method to GetTensorOrSelectedRowsFromVar()

* fix operator

* refine MultiOutput

* fix MultiOutput
test=develop

* disable test_dist_save_load
test=develop

* fix elementwise_op
test=develop

* add get_sparse_as_op
test=develop

* add info for check
test=develop

* rename get_sparse_as_op with extract_rows_as_op.
test=develop

* elementwise doesn't support selected_rows

* fix regularizer

* remove extract_rows_as
test=develop

* fix ci
test=develop

* add test for sum_op

* fix regularizer
test=develop

*  test=develop

* fix pserver weight decay multi inputs test=develop

test=develop