message: Add C++17 standard/flags to CMakeLists
  For VS2017, there's currently a CMake workaround needed
diff: @@ -10,7 +10,7 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
  # This sets the C++ standard to c++14 and required for all the following targets that we define.
  # It has no effect on MSVC though - we thus define more specific requirements for each executable target respectively.
  # Also it will not apply to the eos library target, since it is an INTERFACE_LIBRARY, and these properties do not apply to interface libraries.
  -set(CMAKE_CXX_STANDARD 14)
  +set(CMAKE_CXX_STANDARD 17)
  set(CMAKE_CXX_STANDARD_REQUIRED ON)
  set(CMAKE_CXX_EXTENSIONS OFF) # This makes CMake use -std=c++11 instead of -std=gnu++11
  # This list is likely not complete, but it should be sufficient to error out on old compilers that we cannot build on:
  @@ -110,6 +110,10 @@ set(HEADERS
  add_library(eos INTERFACE)
  target_compile_features(eos INTERFACE ${EOS_CXX_COMPILE_FEATURES})
  +# Add c++17 flag for VS2017:
  +# Results in a warning that both /std:c++14 and c++17 are defined but we can't get around that until CMake properly supports it.
  +target_compile_options(eos INTERFACE "$<$<CXX_COMPILER_ID:MSVC>:/std:c++17>")
  +
  # Add header includes:
  target_include_directories(eos INTERFACE "include")
  target_include_directories(eos INTERFACE ${CEREAL_INCLUDE_DIR})
  