fixes for issue 4

I had the same issue as the person who started that issue and was able to fix it by reading through all the comments.

Working back from there, I changed the instructions to read what likely would have worked the first time.

More speculatively (since I don't think that I've exercised any zmq functionality yet), I changed the zmq install to be a regular rockspec install.  This may be the wrong thing to do if you're relying on some stuff that hasn't made it into the release rock yet (1.1-1 is what I got). Happy to fix anything if I've goofed up.