* thorough clean

* delete_DS_Store

* update_1.3

* thorough clean

* delete_DS_Store

* [Don't merge now]update_install_doc (#643)

* update_install_doc

* follow_comments

* add maxdepth (#646)

* upload_md (#649)

* update_version (#650)

* Translation of 16 new apis (#651)

* fix_windows

* thorough clean

* delete_DS_Store

* update_commitid1.3 (#641)

* update inference c++ API doc (#634)

* update inference c++ API doc

* fix link

* learning_rate_modifier_en

* Review

* File path

* pooling_en

* Review

* File path

* detection_en

* Review

* file path

* data_feeder_en

* Review

* file path

* upload activationsen.rst

* Update activationsen.rst

* Update activationsen.rst

* Review

* file path

* upload async_trainingen.rst

* Review

* upload cpu_train_best_practiceen.rst

* Review

* upload large_scale_sparse_feature_trainingen.rst

* Review

* sparse_update_en

* Review

* file path review x2

* conv_en

* Review

* Review

* optimizer_en

* Review

* file path

* tensor_en

* Review

* file path

* executor_en

* Review

* file path+review x2

* model_save_reader_en

* Review

* delete redundant

* inference_en

* Review

* upload sync_trainingen.rst

* Update sync_trainingen.rst

* Update sync_trainingen.rst

* Review

* upload mathen.rst

* Update mathen.rst

* Review

* file path

* upload /sequenceen.rst

* Review

* file path fix

* data_in_out_en

* Review

* Correct file path

* delete redundant

* programming_guide_en

* Review

Update layers_cn.rst

* upload cluster_train_data_en.rst

* Review

* polish

add explanation of auc

* control_flow_en_loss_function_en_metric_en

* Review x3

add explanation of auc

* upload memory_optimize_en.rst

* Review

* fix jargon

* Fix memory ==> video memory

* upload parallel_executor_en.rst

* Review

* Redundant

* Change api guides directory

* fix wrong ref

* Update memory_optimize.rst

* remove v2

* remove mobile

* check_1.3_api_update

* add launch mp distributed job

* fix comment

* update by comment

1. add index for all English version of "进阶使用"
2. replace legacy softlinks to howto/optimization & dev/new_op_en with original file

add gpu support