AbstractPattern now implements AstNode
Removed QueryToken around aggregateQueries
AbstractPattern refactoring

o Removed AbstractPattern in the 1.9 parser
o Moved AbstractPattern from the 2.0 parser up one level so all parsers can use it
o Changed the 1.9 parser to emit the new AbstractPattern
Merge pull request #741 from systay/cypher-refactorings

Cypher refactorings