- Vectors that point far outside the frame don't work, although the special
case of them pointing right beside the frame works. So test for vectors
pointing farther away.
- Update include directory for greatest.
- Add our own Github fork of greatest as a submodule, in case we want to
improve it and push changes upstream easily in the future.
- Update existing unit tests to use greatest.
- Update Visual Studio project to remove traces of seatest and include greatest.