Update PHPParser

Make resolveExpressionNodeToType() handle null (felixfbecker#277)

Caching (felixfbecker#260)

Automatically index stubs on composer install (felixfbecker#269)

Use JetBrains PHPStorm stubs from packagist (felixfbecker#264)

* Use JetBrains PHPStorm stubs from packagist

* Fix path

Make Index an EventEmitter (felixfbecker#255)

Don't crash if indexing fails

Implement global references protocol extension (felixfbecker#236)

Allow overriding (felixfbecker#229)

* Add missing documentLoader property

* Make PhpDocumentLoader->contentRetriever public

Fix wrong function call in DefinitionResolver