Merge branch 'neo4j/1.9-maint' into master

Conflicts:
	community/cypher/src/main/scala/org/neo4j/cypher/internal/executionplan/builders/ColumnFilterBuilder.scala
	community/cypher/src/main/scala/org/neo4j/cypher/internal/executionplan/builders/EmptyResultBuilder.scala
	community/cypher/src/main/scala/org/neo4j/cypher/internal/executionplan/builders/ExtractBuilder.scala
	community/cypher/src/test/scala/org/neo4j/cypher/ExecutionEngineTest.scala