* modify doc for Attr(data_format) or Attr(data_layout) and add Raises information, test=develop

* modify doc of conv3d_transpose for Raises information, test=develop

fix doc according to reviews.test=develop

* add instance norm

* update conv2d 
conv3d
conv2d_transpose
conv3d_transpose
batch_norm
cos_sim
cross_entropy
npair_loss
dropout
img_conv_group cn doc

* http://newicafe.baidu.com/issue/DLTP-2069/show?from=page

* fixed one error of develop

* fixed one error of api_cn

* fixed some errors of api_cn

* fixed some errors of api_cn

* fixed two errors.

* fixed two errors

* fixed one error.

* fixed one error

* fixed one error.

* fixed two errors.

* fixed one error.

* fixed two errors

* fixed two links

* synchronize api_cn with the api_en of develop.

* updated develop/api_cn

* update the api_cn of develop

* update api_cn of develop

* fixed some errors

* Delete .DS_Store

* Delete .DS_Store

* Delete .DS_Store

* Delete .DS_Store

* Delete .DS_Store

* fixed some wrong links

* fixed two links

* fixed two links and some error.

* fixed some errors.

* fixed two links

* http://newicafe.baidu.com/issue/DLTP-1771/show?from=page

* http://newicafe.baidu.com/issue/DLTP-1647/show?from=page

* http://newicafe.baidu.com/issue/DLTP-1529/show?from=page

* Update natural_exp_decay_cn.rst

* Update Reader_cn.rst

* http://newicafe.baidu.com/issue/DLTP-1907/show?from=page of develop