Adding only a single recovery rule for now.
The API is now:
* throwOnError parser option must be disabled.
* List of Errors is available through $parser->getErrors(). This
method is available either way.
* If no recovery is possible $parser->parse() will return null.
(Obviously only if throwOnError is disabled).
When parsing on PHP 7 we will no longer be able to deal with
code that contains invalid octal literals. Currently we'll fatal,
after engine exceptions land we'll throw an exception instead.
