Created by: qingqing01

1. Add job=time in trainer, which can print time without to enable the option WITH_TIMER on.
2. Add ConvProjection to reduce gpu memory for GoogleNet.
3. Use TmpMatrix in CudnnConvLayer and ConvProjection to reduce gpu memory.

This pull extracts the code in paddle from the pull https://github.com/baidu/Paddle/pull/217