Upgrade to gtest/gmock 1.8

[sawilde]

Currently using 1.7 with a copy we keep in a zip file, 1.7 uses std::tr1 which has been deprecated and we are suppressing using the following define

_SILENCE_TR1_NAMESPACE_DEPRECATION_WARNING

[ ] look to see if we can pull the zip from https://github.com/google/googletest/releases