Embed per-extension systemlibs
Implement ZipArchive

This diff implements ZipArchive class and zip functions of
PHP, as described in http://php.net/manual/en/class.ziparchive.php and
http://www.php.net/manual/en/ref.zip.php respectively.

This diff is not complete, summary and test plan will be updated as
the code revised.  Also I should land a third-party repo commit as
well, libzip, before I land this code.

Reviewed By: @ptarjan

Differential Revision: D1040058