Patch for /lib/convex_hull.cpp

```
Need to resize vector instead of reserve
```

Original issue reported on code.google.com by `fabian.g...@gmail.com` on 28 Apr 2015 at 3:04

Attachments:
- [convex_hull.cpp.patch](https://storage.googleapis.com/google-code-attachments/carve/issue-80/comment-0/convex_hull.cpp.patch)
