Rewrite publish.sh to make it possible to automate

Add respec as a submodule since we need both respec itself and the
respec2html.js script. As a bonus, we now track which version we're
using, so we can decide when to upgrade and look for bugs.
Require -f or manual confirmation in publish.sh
Merge pull request #11 from foolip/auto-publish

Rewrite publish.sh to make it possible to automate