Logging performance optimizations:
* Added custom Jetty logger that caches isDebugEnabled
* Changed LogbackService to cache isDebugEnabled
* Added isDebugEnabled check before toString() in HighPerformanceCache
Only add security filter if there are security rules
License header fix
Debug cache is now no longer static.
Added comment that the request log needs to decorate all other handlers.
Handle pruning old format logs, Fixes #2265
Added +UNWIND+ to Cypher

UNWIND can be used to transform a collection into individual rows.
Minor changes to UNWIND

o Added more a few more tests for edge cases
o UNWIND now does not remove anything from scope,
  only adds a new identifier for the elements
o Tweaked the documentation
Add UNWIND to shell
Fix GC overhead of XidImpl

- Only allow equality of XidImpl instances, not the Xid interface,
  reasoning being that hashCode cannot be equal to other xid impls since
  there is no standard, and getting a xid that isn't a xidimpl is an error,
  since the xids come from our tx manager, we do not manage other xids.

- Don't copy the branchID and globalId arrays on every equaylity check
Merge pull request #2343 from jakewins/1.9-prune-oldlogs

Handle pruning old format logs, Fixes #2265
Changes ClusterSettings.server_id to be an InstanceId instead of an integer
Merge branch '1.9-maint' into 2.0-merge-1.9

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/transaction/xaframework/LogPruneStrategies.java
Merge branch '2.0-merge-1.9' into 2.1-merge-2.0-2
Fixed a memory leak in DiskLayer on HA restart.

- DiskLayer no longer uses an anonymous inner class for the lazy property
  loading, as this would cause a memory leak on data source restarts.
Merge pull request #2354 from chrisvest/2.0-merge-1.9

2.0 merge 1.9
Merge pull request #2355 from chrisvest/2.1-merge-2.0-2

2.1 merge 2.0 again
Include javadocs with the manual.
Fix bug that would not pick up node by id in some cases
Merge pull request #2358 from systay/node-by-id-no-matter-case

Fix bug that would not pick up node by id in some cases
Better code: use foldLeft rather than treeFold