Rename doc/howto/cross_compiling into doc/mobile

fix bugs of softmax_with_cross_entropy op.

Put files to platlib

Fix the doc for Momentum and Adam optimizer.

The engine library need to link paddle_pserver and paddle_network on linux.

Refine sequence max-pooling and add unit testing of gradient check.

Update docker_install_cn.rst fix nodebook to notebook

Add GRU Operator

fix nodebook to notebook

Fix type for unit test of huber_loss_op.

Bugs fix and expose sub_seq_layer.

add MKLDNNAddtoLayer

* Add GetFineGrainedLoDLength and AppendLoD

* Follow comments and fix bugs

* fix a compile error

* fix a compile bug

* Use stable_sort in lod_rank_table

It is easy to debug and test when use `stable_sort`and the time
complexity is not changed.

* Add LoDTensorArray

* fix m_ops

* fix activation op

* polish p ops

* fix precision_recall

* fix linear_chain_crf_op

* small fix

* polish r operator docs

* fix on naming convention

* Adding the doc format for AdaDelta

* Updating the documentation for Adagrad, Adam and Adamax

* Updating the auc op

* Fix review comments

* Updating doc for Batch Norm

* Updating the cast op

* Updating the clip op

* Fixing review comment

* Fixing review comment:

* Small change to restart PR_CI

* Adding documentation for seq_expand

* Adding documentation for seq_concat_op

* Adding documentation for sequence_conv

* Adding sequence_pool

* Fixing review comment

* Adding sequence_softmax

* Updating doc for sigmoid_cross_entropy_with_logits

* Doc fix for smooth L1 loss

* Adding doc for softmax_op

* Added doc for softmax_with_cross_entropy

* Adding documentation for transpose_op

* small change to restart TeamCity CI

It is easy to debug and test when use `stable_sort`and the time
complexity is not changed.

Add print_operators_doc to Paddle Docker Image