The reason for adding the function is exemplified in the following hypothetical code:

mem = memory(name=None, size=256)
hidden = fc_layer(input=mem)
state = hidden + x
mem.set_input(state)

In the above code segment, it would be very annoying if we require the user to provide
the name at memory() call because the layer name of state is automatically generated
and is not easy to set it.

Change-Id: I918bf1d3d5c26addd88a6f7021e98b3e0e9df494

* Because currently Paddle only use protobuf 3.

* It gets wrong command line arguments before.

* math => layer_math
* Fix #903

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