Updating after integrating latest changes from Chuck's main.
Updating after integrating latest changes from Chuck's main.

crcresearch/smartcontainers,Omegaice/smartcontainers,dahuo2013/smartcontainers,charlesvardeman/smartcontainers,Omegaice/smartcontainers,dahuo2013/smartcontainers,Omegaice/smartcontainers,crcresearch/smartcontainers,crcresearch/smartcontainers,dahuo2013/smartcontainers