Use the latest version of PHP-Parser

Previously, 0.9 was used.
Main changes:
	•	folder PHPParser moved to PhpParser
	•	PhpParser contains namespaces
	•	Rascal visitor generators are updated (the code is generated with the files)
	•	AST2Rascal class is moved to RascalPrinter
	•	AST2Rascal now only contains stuff to call RascalPrinter
	•	Generated tests are added (based on the previous version of the parser)
	•	Removed the extra added Expression node (\Node\Stmt\Expr)