Release v1.0.0
Pull text-encoding from npm instead of from vtt.js bower dist.

The text-encoding lib (formerly stringencoding) was previously not
on npm and so I elected to pull it from vtt.js bower distributable
instead of using a git submodule, since the current version of it
was broken. It's on npm now so we can pull directly from there and
get rid of our bower dependencies.
Release v1.1.0
Add PhantomJS install info to README.