The previous code could potentially be a compilation issue waiting to
occur, given we forward declare the type for a std::unique_ptr. If the
complete definition of the forward declared type isn't visible in a
translation unit that the class is used in, then it would fail to
compile.
Defaulting the destructor in a cpp file ensures the std::unique_ptr's
destructor is only invoked where its complete type is known.
* get rid of boost::optional
* Remove optional references
* Use std::reference_wrapper for optional references
* Fix clang format
* Fix clang format part 2
* Adressed feedback
* Fix clang format and MacOS build
* Added a context menu on the buttons including Clear & Restore Default
* Allow clearing (unsetting) inputs. Added a Clear All button
* Allow restoring a single input to default (instead of all)