* fix huber_loss ans npair_loss doc and example code, test=document_fix

* remove disable_static in example code, test=document_fix

* remove huber_loss and refine npair_loss example code, test=document_fix

* remove huber_loss in functional/__init__.py, test=document_fix

* refine grid_sample and temporal_shift

* migrate code example and doc

* numpy -> paddle in conv. test=develop

functionality provided by `normalize`

* fix example code

* rename var to tensor

* remove static

* fix return type

* add float64 input to ctc_loss

* modified error message of  warpctc

* update repo and tag of warpctc

* add test for warpctc with float64 input

* modified warpctc.cmake to make sure build always

* resolved sample code bug of warpctc

* add core.ops in warpctc dygraph

* fix a bug of test

* fix pool bug, test=develop

* fix coverage,test=develop

* fix bug, test=develop

Fix conv deepwise bug when in_channels=1.

* fix summary rnn

* fix kl_div bug when input shape is [1] and reduction is batchmean

* fix weight

* fix weight and fix doc

* fix embeeding padding idx

* add UT

* fix interval

* fix typo for interp_v2,test=develop

* align with torch, test=develop

* add area mode, test=develop

* fix bug, test=develop

* format notes, test=develop

* update for converage, test=develop

* fix bilinear, test=develop

* fix bicubic, test=develop

* fix typo, test=develop

* fix coverage, test=develop

* fix helper.input_dtype, test=develop

* polish notes, test=develop

* polish notes, test=develop

* polish notes, test=develop

update doc of paddle.to_tensor

* fix

* fix doc, test=document_fix

* fix dropout bug in backward when input is 1d tensor, test=develop

* add test case and refine error message, test=develop

* refine error message, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* fix norm bug, test=develop

* add embedding 2.0

* add embedding support input int32

fix doc, use to_tensor for the loss ops

* fix bug

* add version check

* fix docs, test=document_fix

* fix formula, test=document_fix

For normalize op, remove special treatment of one-dimensional input, add check for one-dimensional input (#26747)

For normalize op, remove special treatment of one-dimensional input, add check for one-dimensional input

* Add RNN related apis in paddl.nn
test=develop

* new rnn api, cell almost done

* add new progresses in rnn APIs for 2.0

* refine rnn APIs and docstrings.

* add unittets

* disable gpu tests when paddle is not compiled with cuda support

* remove unnecessary imports

* fix docstring

* add to no_sample wlist

* backport to python2 to avoid yield from

* add **kwargs, fix typos

* update docstrings for birnn

* rename argument for SimpleRNN and SimpleRNNCell, fix sample code

* add default value for initial_states in fluid.layers.birnn
Co-authored-by: Nguosheng <guosheng@baidu.com>