* math => layer_math
* Fix #903

* Partially fix #622

In order to keep consistent with other evaluators, an extra parameter
label is add to chunk_evaluator. Document and demos are modified
accordingly.

These three parameters have already been moved to model_average. Leaving
them here will cause duplicate keys in kwargs

* error because merge of #711. The old issue don't check pre-commit
  hooks.

test_rest_hook.py => test_reset_hook.py

Change-Id: I84909ade4a1ea2bec4311264626dd000cd6bc86c

To solve this, we maintain the list of DefaultNameFactory used in by trainer_config_helper,
and reset the state at the beginning of each parse_config call.

Change-Id: I13c7574dc8f0b6bc6f6b7c92eb425e2c52c926e8

The values for ____crf_layer_0__.w0 in python/paddle/trainer_config_helpers/tests/configs/protostr/test_cost_layers.protostr is not correct due to swapped height and width in config_parser

The dims for crf and crf_decoding layers are wrong, i.e. height and width are swapped.

Added a test in test_NetworkCompare to verify cudnn and exconv, fixed a bug in cudnn_conv in dealing with groups

* Make float equal works well.
  * compare 0.01 and 0.009999999999 will return true.