toTreeString implemented by Visitor pattern
Using implicit position in tests when possible
Merge pull request #2267 from davidegrohmann/cleanup-test-implicit-pos

Using implicit position in tests when possible
Introduce OptionalPipe and ApplyPipe and use for optional match
Planning of outer joins
First stab at a outer hash join implementation
Add code to make sure outer join handles nulls correctly
Merge pull request #2271 from boggle/ronja-optional-match

Optional Match for Ronja
Adds more inform to violation exception
Merge branch '2.0-maint'
Fixed a store migration test that was disabled for Windows
Merge branch '1.9-maint' into 2.0-maint

Conflicts:
	community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/UpgradableDatabaseTestIT.java
Merge branch '2.0-maint'

Conflicts:
	community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/UpgradableDatabaseTestIT.java
Merge pull request #2266 from davidegrohmann/tree-string-visitor-pattern-cleanup

toTreeString implemented by Visitor pattern
Optimize NodeOuterHashJoinPipe
Split up applyOptional and optional
Add a planner for optional expand
Merge branch 'optional-expand'
Add OptionalExpandPipe
Ensure Cypher range() works with negative step values

Fixes #2269