A tiny fix in PyDataProvider2

Remove utils/CommandLineParser.h

Change float to real in NormLayer.h

add rnn_cn.md

Fix data provider bug in srl demo

Fix typo in PyDataProvider2.py

Add const to GradientMachine::eval

Adding namespace in timing macros

Once encoutering a single sample whose size is larger than batch size,
the provider will yield empty batch and terminate the current pass unexpectedly
if can_over_batch_size=False.

priorbox layer for Single Shot Multibox Detection Network

* hidden decorator kwargs in DataProvider.__init__
* also add unit test for this.

Support user specified label input in tests

Remove not used params in GradientMachine::start

Fix bug in config_parse.py when batch_norm layer is used in RecurrentLayerGroup

travis for check broken links

Remove unused cost parameter in ParameterUpdater

change float to real in two tests

Sometime those macros are used under different namespaces. We need to use namespace ::paddle
to make it compile correctly.

Change-Id: I57a6d6ec8cd0d680b584aab62d72a35c226a24a4

support UBUNTU MIRROR and modify doc