Now that clang-format makes [[nodiscard]] attributes format sensibly, we
can apply them to several functions within the common library to allow
the compiler to complain about any misuses of the functions.
* 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)
Lioncash
zhupengfei
wwylele