Switch to modern OpenGL

[ChihHao-Su]

The fixed function pipeline(immediate mode APIs) has become obsolete, and has been removed from core OpenGL 3.1 and above.

[keainye]

近期正打算换渲染引擎，OpenGL实在是太原始了，大部分精力放在基础设施上并不是一件好事。

Going to change a render recently. OpenGL is too primitive for this project. It is not good to think too much on the infra.