bareopt

A simple subset of std::optional for c++11 and above. It should be mostly compatible with std::optional, except for the additional support to optional references.

This optional does not have:

• constexpr support
• conditionally explicit constructors
• triviality propagation (except for destructor triviality)
• relational operators
• probably something else

Some of the tests have been taken from this optional implementation, which you should probably be using anyways.