Add header guards.
Add header guards.

awensaunders/kernel-of-truth,Herbstein/kernel-of-truth,iankronquist/kernel-of-truth,iankronquist/kernel-of-truth,iankronquist/kernel-of-truth,iankronquist/kernel-of-truth,Herbstein/kernel-of-truth,Herbstein/kernel-of-truth,awensaunders/kernel-of-truth,awensaunders/kernel-of-truth,iankronquist/kernel-of-truth