* 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)
* Removed use of raw QTimer* pointer.
* Update to use type-safe QObject::connect.
* getKeyName can be a static local function.
* Prefer to use function arguments instead of member variables.
* Store Qt::Key instead of converting string back into keycode.
zhupengfei