Always initialize wrappers, regardless of PG(allow_url_fopen).

Always initialize wrappers, regardless of PG(allow_url_fopen).
Add is_url field to wrapper structure; the stream wrapper openers
will disallow opening is is_url && !PG(allow_url_fopen).
Add infrastructure for stat($url) and opendir($url).
Tidy up/centralize code that locates and instantiates wrappers for the
various operations.
Implement opendir for plain files.
Make the PHP opendir and dir functions use the streams implementations.
Add modelines for syntax highlighting the pear scripts in vim