Changelog:

• Improved generation of registration hooks
• Registration hooks can now be disabled using the no_register_json_converters config flag
• Added serialization for std::chrono::* (basic times, i.e. hours, minutes, seconds, ...)
• Added std::optional serialization
• Added std::variant serialization
• Added helper macros for converter registration with inverse typedefs
• Improve behaviour/design of registration methods
• Add StrictBasicTypes validation flag to test if basic types like int, double, ...
• Add option to ignore the STORED attribute of serialized properties ( #18 )
• Requires C++17