Add array method dereference support to xhpast.
Summary: Adds support for array method dereferencing, e.g. $foo->bar(). Bumps XHPAST version. Ref T4334.
Test Plan: Wrote two failing unit tests for language parsing abilities using the specific errors mentioned in T4334. Hacked away at the parser importing bits from Zend's zend_language_parser.y until they passed.
Reviewers: epriestley, Blessed Reviewers
Reviewed By: epriestley, Blessed Reviewers
Subscribers: epriestley, Korvin
Maniphest Tasks: T4334
Differential Revision: https://secure.phabricator.com/D8611