Merge branch 'fix-gmock' into 'master'

COMP: Update Google Test to fix compilation on msvc 15 2017

See merge request iMSTK/iMSTK!247

CMake/External/External_GoogleTest.cmake

@@ -4,7 +4,7 @@
 include(imstkAddExternalProject)
 imstk_add_external_project( GoogleTest
   GIT_REPOSITORY https://github.com/google/googletest.git
-  GIT_TAG release-1.8.0
+  GIT_TAG dc043e1ca6bd509a92452ed54e817b6979869372
   INSTALL_COMMAND ${SKIP_STEP_COMMAND}
   CMAKE_CACHE_ARGS
     -DBUILD_GMOCK:BOOL=ON