Settings menu improvements (#770) * ButtonGroup can hold a value and treated as a form option * Switch Video Mode, VSync, Anti-Aliasing, Texture Filtering, and Game Language from DropDown to ButtonGroup * Each settings page has its own Restore Default/Cancel/Save Changes button * Fixed Save Changes button not highlighting when things are changed * Implement Restore Default action for all settings * Added .is-label to Glass styles, used it for settings labels * Stage keybind changes and only applied after pressing Save Changes