Used the v1.8.x branch of the googletest to avoid C++11 compatibility problems.

test/gtest/CMakeLists.txt

@@ -4,6 +4,7 @@ include(ExternalProject)
 
 ExternalProject_Add(googletest
     GIT_REPOSITORY https://github.com/google/googletest.git
+    GIT_TAG v1.8.x
     CMAKE_ARGS -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_DEBUG:PATH=DebugLibs
                -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_RELEASE:PATH=ReleaseLibs
                -DCMAKE_CXX_FLAGS=${MSVC_COMPILER_DEFS}