ltui v2.6

Changes

• Add exit tip to mconfdialog
• Improve lcurses to register more virtual keys
• Improve back and select in mconfdialog

改进

• mconfdialog 添加退出确认提示
• 改进 lcurses 注册更多的虚拟按键
• 改进 mconfdialog 操作体验，返回上级页面自动切换到选择按钮