说明：  基于Unity 5.3.5f1 (64-bit)，用C#编写的，从外部动态加载Raw格式图片，做为Terrain的高度图.目前可能还不够完善，但可以做为一个读入Raw格式高度图的参考，网上的代码是在太少了。不要有中文名的路径，在场景中新建一个地形长宽为512*512，新建一个空对象，将ReadRawImg.cs赋给这个空对象
(Based on Unity 5.3.5f1 (64-bit), prepared by the C#, the external dynamic loading Raw format pictures, as a height map Terrain. At present may still not perfect, but can be used as a height map read Raw format reference, online code is too little.)