* modify cond while_loop to paddle.static.nn.cond

* modify crop_tensor to paddle.crop

* modify Variable to paddle.static.Variable

* remove nn.beam_search, nn.beam_search_decode, nn.gather_tree

* remove bpr_loss, center_loss, rank_loss, smooth_l1, teacher_student_sigmoid_loss, edit_distance, sampled_softmax_with_cross_entropy in nn.functional

* remove apis in nn.functional.learn_rate.py

* remove pool2d, pool3d, adaptive_pool2d, adaptive_pool3d in nn.functional

* remove apis in nn.functional.vision

* remove erf, soft_relu in nn.functional.activation

* remove apis in nn.functional.extension

* remove nn.functional.rnn

* remove hash from nn.functional.lod

* remove row_conv from nn.functional.extension

* remove one_hot, pad2d, pad_constant_like from nn.functional.common

* remove nn.gather_tree, nn.BilinearTensorProduct, nn.Pool2D, nn.Pad2D

* remove apis from optimizer.__init

* remove tensor.creation.fill_constant

* remove elementwise_mul in nn.functional.common and  modify to paddle.multiply

* remove  tensor.stat.reduce_mean

* remove reduce_all, reduce_any in tensor.logic

* remove apis in tensor.math

* remove apis in tensor.__init__

* remove has_inf, has_nan in tensor.search

* remove apis in framework.__init__

* remove apis in paddle.__init__

* remove apis in nn.functional.__init__

* modify removed alias apis to raw api in doc and unittests

* fix remove grid_sample bug

* modify removed alias apis to raw api in doc and unittests

* modify removed alias apis to raw api in doc and unittests

* modify removed alias apis to raw api in doc and unittests

* modify removed alias apis to raw api in doc and unittests

* modify removed alias apis to raw api in doc and unittests

* modify removed alias apis to raw api in doc and unittests

* delete alias api relastions in doc

* reserve paddle.compat, paddle.sysconfig

* remove unittest for paddle.reduce_all, paddle.reduce_any

* modify removed alias apis to raw api in doc and unittests

* recover paddle.save and paddle.load

* resolve conflicts

* fix sample code missing paddle.enable_static() bug

* fix sample code missing paddle.enable_static() bug

* fix to_string sample code error

* update assign/cast/linspace/addcmul op doc for 2.0 api,test=document_fix

* fix bug about cast doc for 2.0 api,test=document_fix

Update code examples for api2.0 

add paddle.tensor.linalg.diag API, diag_v2 OP and CUDA kernel.

* Support LoDTensorArray in reverse_op test=develop

* polish en doc and unittest code test=develop

* refine sample code test=develop

* add example of LoDTensorArray test=develop

* fix typo test=develop

* fix error log: resahpe, range, reverse.

python API(get_tensor_from_selected_rows and tensor_array_to_tensor)error message enhance, test=develop (#23636)

* error message enhancement create_parameter create_global_var, test=develop

* use six.PY2 to use long, test=develop

* fix input dtype for create_parameter, test=develop

raw doc: bool, float15, float32, float64, int8, int32, int64, uint8.
new doc: bool, float16, float32, float64, int8, int32, int64, uint8. 

* Add the support of bool list for assign value, test=develop
* Fix the assign op test case for bool dtype, test=develop

API(has_inf, has_nan, cumsum, fsp_matrix, increment) error message enhancement, test=develop (#23769)

* API(argsort, argmax, argmin, cast, diag) add error message，and the same time add the test cases for those apis.