Correct CONTRIBUTING typos.
Merge pull request #724 from cirosantilli/typos

Correct CONTRIBUTING typos.
Added XSS escaping to li/repo.html (fixes prose/prose#729).
Merge pull request #730 from ashmind/li-repo-xss

Added XSS escaping to li/repo.html (fixes prose/prose#729).
Merge branch 'master' into gh-pages
Updated to latest