Remove the 'vector' from the start of the version (otherwise the
tarballs are called vector-vector-[...].tar.gz). The jenkins
script already creates these files, so update accordingly.
html_url is in the top-level 'commit' object, not in commit.commit.
Also factor some code out for legibility. Seriously, what's with stuffing
everything into inline functions?
This has been rewritten to use browser-request rather than whatwg, so remove
the import, which was causing the build to fail on npm 2. (It worked, for the
wrong reasons, on npm 3.)
