separate testing environment

-Separate main for running unit tests
-Move unit tests into testing folder

Engine/lib/gtest/CMakeLists.txt

@@ -0,0 +1,39 @@
+# Note: CMake support is community-based. The maintainers do not use CMake
+# internally.
+
+cmake_minimum_required(VERSION 3.5)
+
+if (POLICY CMP0048)
+  cmake_policy(SET CMP0048 NEW)
+endif (POLICY CMP0048)
+
+if (POLICY CMP0069)
+  cmake_policy(SET CMP0069 NEW)
+endif (POLICY CMP0069)
+
+if (POLICY CMP0077)
+  cmake_policy(SET CMP0077 NEW)
+endif (POLICY CMP0077)
+
+project(googletest-distribution)
+set(GOOGLETEST_VERSION 1.13.0)
+
+if(NOT CYGWIN AND NOT MSYS AND NOT ${CMAKE_SYSTEM_NAME} STREQUAL QNX)
+  set(CMAKE_CXX_EXTENSIONS OFF)
+endif()
+
+enable_testing()
+
+include(CMakeDependentOption)
+include(GNUInstallDirs)
+
+#Note that googlemock target already builds googletest
+option(BUILD_GMOCK "Builds the googlemock subproject" ON)
+option(INSTALL_GTEST "Enable installation of googletest. (Projects embedding googletest may want to turn this OFF.)" ON)
+option(GTEST_HAS_ABSL "Use Abseil and RE2. Requires Abseil and RE2 to be separately added to the build." OFF)
+
+if(BUILD_GMOCK)
+  add_subdirectory( googlemock )
+else()
+  add_subdirectory( googletest )
+endif()