modify directory structure in source code

Update sentiment_analysis.md

Sync Release Branch => Develop

Add Paddle Usage Stats Scripts.

Fix shuf/gshuf choose bug

#487

Modified API to use FLAGS_use_gpu as useGpu default value

sentiment analysis translation (#270)

modify first level directory of english doc

Fix some install package errors.

* Mount local Paddle instead of git clone from remote.
* Use official chinese ubuntu source instead of 163 mirror.

Bumping up version number to v0.9.0a0

add layer check for recurrent_group

fix bug for issue 345

Fix forwardTest for ids in python swig.

* unittest need to be added. But fix the bugs first.

Feature/pre commit hooks scripts

Add ScalingProjection

Change-Id: Ic80845c892c96c37a0df0ddc433fe1aeaa5a9d1c

out = w * input
where w is a parameter of size 1

Change-Id: Ife682d62323ceb1a20cbbf6269421b20a862d888