More namespace cleaning.
remove 2 using per jeff's comment
fixing std::min and std::max and std::abs: using them in default will make nvcc unhappy.
Merge branch 'dev' of https://github.com/BVLC/caffe into dev

Conflicts:
	src/caffe/common.cpp
lint
Merge pull request #718 from Yangqing/dev

More namespace cleaning.