renderSettings() {
    // Only windows and mac support window opacity
    const supportsOpacity = this.platform === 'darwin' || /^win/.test(this.platform);
    if (!supportsOpacity) {
      return null;
    }

    return (
      <div className="settings-btn">
        <button className="btn-action btn btn-dark" onClick={ this.toggleSettings }>
          { !this.state.settingsShown ? <i className="fa fa-cog"/> : <i className="fa fa-times-circle"/> }
        </button>
        { this.state.settingsShown && <Settings/> }
      </div>
    );
  }
Renders the settings button for changing opacity
@return {*}