Add a linter rule to detect call-time pass-by-reference

Summary: Call-time pass-by-reference is an awful "feature" of PHP that is deprecated and removed in PHP 5.4 (see http://us1.php.net/manual/en/migration54.incompatible.php). Add a linter rule to ArcanistXHPASTLinter to detect the use of this feature and raise an error.

Test Plan: Added a test case for arc unit.

Reviewers: Blessed Reviewers, epriestley

Reviewed By: Blessed Reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D10537