Upgrade To PHP Parser 1.0

This upgrades us to php parser 1.0.

~~I've bumped our version from 1.0 to 1.1 for this change. A php parser stable tag will come in 2 week's time (https://github.com/nikic/PHP-Parser/issues/125#issuecomment-53990700), so if you like this, it might be a good idea to stamp the `1.1.0` release after php parser has a stable tag.~~ **The version bump was done as part of another pull.**

It might be a good idea to stamp the `1.1.0` release after php parser has a stable tag.