读取STL格式文件代码，通过建表简化拓扑结构，获取模型的最大值，最小值等参数。-STL format file to read the code, through the construction of simplified topology table, access to model maximum and minimum values ??and other parameters.

stl文件的读取，删除重复的点和边，进行拓扑重构，得到新的数据结构-stl file to read, delete duplicate vertices and edges, the topology reconstruction, new data structures