Updated to gmock-1.7.0

The previous gmock-1.6.0 was failing to compile on Mac OS 10.9
with clang-500.2.79 from XCode-5.0.2 due to issues with finding
the TR1 tuple library.

Update C++11 check to check for constructs used in Google Mock and
suppress valgrind reachable memory warnings on Mac OS X about
localtime.

Change-Id: I0703e581373aba8d2cf5cf42b9443a76ac0f6032