Resolves #23 by including an example of setting MacOS Environment Variable with liboqs.dylib.
I removed reference to the specific platform instructions, because it was ambiguous about whether that referred to the current repo or the liboqs repo.
I notice an opportunity to include links to sponsor organizations et al. I kept this focussed on issue-23 for future tracking, but more than happy to go through it, since I already have a fork cloned etc.
Resolves #23 by including an example of setting MacOS Environment Variable with liboqs.dylib.