Invalid config keys are silently ignored

[abextm]

Gestures which previously used to work, such as the following no longer work silently. This is because pixels was changed to interval (without a release note :cry:). Keys that are not recognized should be logged, though it would also be nice for the pixels->interval alias to come back.

                    action = {
                        type: "Gestures";
                        gestures: ({
                                direction: "None";
                                mode: "OnRelease";
                                action = {
                                        type: "Keypress";
                                        keys: ["KEY_MUTE"];
                                };
                        }, {
                                direction: "Right";
                                mode: "OnFewPixels";
                                pixels: 12;
                                action = {
                                        type: "Keypress";
                                        keys: ["KEY_VOLUMEUP"];
                                };
                        }, {
                                direction: "Left";
                                mode: "OnFewPixels";
                                pixels: 12;
                                action = {
                                        type: "Keypress";
                                        keys: ["KEY_VOLUMEDOWN"];
                                };
                        });

Additionally the OnRelease gesture now needs threshold: 0; set, when it didn't before, though I am unsure why it worked before.