uniwangwang

### 功能描述 增加画笔颜色的默认初始文件配置选项; 例如增加初始黄色画笔或其他颜色画笔; 当前为红色, 每次都需要更改画笔颜色;

may have some bug if in some rare cases

3

```c++ // edge swapped on the other side of the hull (rare); fix the halfedge reference if ( hbl == INVALID_INDEX ) { std::size_t e = hull_start; do { if...