Synchronize GPU before CPU timers start and stop in net_speed_benchmark
Add Timer to wrap CPU clock_t and GPU cudaEvent_t based timing
Replace CPU timer with newly added Timer to benchmark net speed
Add state machine, boost::posix_time based cpu timer & tests for Timer
Fix the cpplint errors for benchmark Timer
Merge pull request #136 from kloudkl/cuda_timing

Add Timer class unifying CPU and GPU timer and use it in net_speed_benchmark