Create C++ command line program that can smoke test loading/line of sight/etc

[gtker]

When reproducing errors it would be nice to have an upstream program that can be used to verify that the problem is within the library and not in the Python bindings/C API/my application code.

It could make sense to just include this as part of the MapBuilder executable.

I know the MapViewer executable can do this, but it doesn't run on Linux/Mac.