@update - clean and update
@update - Able to play History with challenge mode. Timer in challenge mode is included.
Merge branch 'develop' of https://github.com/lihao6485/ComputeME into develop

Conflicts:
	ComputeMe/ComputeMe/Controller/CMGameResultViewController.m
	ComputeMe/ComputeMe/Controller/CMGetReadyViewController.m
	ComputeMe/ComputeMe/Controller/CMQuestionViewController.h
	ComputeMe/ComputeMe/Controller/CMQuestionViewController.m