* Fix sparse training for trainer_count=1

For trainer_count=1, the gradient machine is NeuralNetwork, which does not create parameter buf for PARAMETER_GRADIENT for sparse update in Parameter::enableType. But gradient parameter buf is still used in SgdThreadUpdater.

* Minor update to comment

* hierarchical rnn document, add new config example

* update inputs_type of label

* add check for unsupported config

* refine hierarchical document

* refine doc title

* update docs, fix paddle to PaddlePaddle

* follow comments

* follow comments to fix bugs

* Correctly handling multiple inputs and integer inputs for recurrent_group

* Fix ScatterAgentLayer for generation

* Revert sequence_(nest)_rnn.conf

Sequences should be sorted according to the number of subsequences they have.

Change-Id: I8e0a8ea6fc2760652d9c76440a539c90860062d3

* modify RecurrentGradientMachine to support hasSubSeq sequence inlinks with the same number of sentence but different number of tokens for each sentence

Change-Id: Ic71f00a4bb346b4fa93e650dfb4b1a0d8d2338b0

Change-Id: Id66da7b7f5bf9ec80cc19b347e4fb822a5a6f197

* by default, synchronize default_stream after resizeAndCopyFrom
* add sync in some places after resizeAndCopyFrom using other streams

* Make layer stack trace shows ThreadId, Forward or Backward.

Change-Id: Iba1477adb8c9115c3a67ff2959bb5c878ca706c7

* Make layer stack trace shows ThreadId, Forward or Backward.

Change-Id: Iba1477adb8c9115c3a67ff2959bb5c878ca706c7

Also add some comments for cost layers.
ISSUE=4580653

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1410 1ad973e4-5ce8-4261-8a94-b56d1f490c56

ISSUE=4586495

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1408 1ad973e4-5ce8-4261-8a94-b56d1f490c56