Fix AddAmmo setting ammo to 99 when trying to add infinite ammo
This affected the portal mission, the crate only gave you 99 portal guns instead of infinite.
Directory for automated tests to test the engine.
Run `ctest` in the root directory of this repository to run all tests.
Run `ctest -R <test name>` to run only the test with the given name.
This requires you to have CMake.