New updates for Simplified Chinese translation.

Added 4 sections as follows:
[Developer]
 Developer Tools = 开发工具
 [General]
 Back = 返回
 [Pause]
 Save State = 状态保存
 Load State = 状态载入
 Continue = 继续
 Settings = 设定
 Back to Menu = 返回菜单
[Graphics]
Stretch to Display = 拉伸显示

Thanks for the help of @raven02 !