update file names and include guards

Core/Tools/PythonFormatting.h

Tests/Core/Performance/CoreIO.cpp

Tests/Core/Performance/Mesocrystal.cpp

Tests/Core/Performance/MultiThreadPerformanceTest.cpp

Tests/Core/Performance/MultiThreadPerformanceTest.h

...Core/Performance/MultiThreadPerformanceTestComponents.cpp

...s/Core/Performance/MultiThreadPerformanceTestComponents.h

Tests/Core/Performance/Multilayer.cpp

Tests/GTestWrapper/google_test.h