Introduce ternary logic in Cypher

o Make Predicate return Option[Boolean] instead of Boolean
o Introduce isTrue that returns false for all cases except when the
   predicate returns Some(true)
o Add logic for IN, ANY, ALL, SINGLE and NONE to handle nulls
o Add a new section on working with nulls to the manual
Remove MSI installer

This never shipped a single MSI and is not plumbed into the reactor.
ImpermanentGraphDatabase.cleanup should delete all nodes

This fixes a bug where certain graphs could confuse the cleanup method
into leaving some nodes behind.
Remove unnecessary code from HaBeanIT
Revisits logging in ElectionState and ClusterConfiguration

Commit 956dc3e1a8edd91a2a3710e2c71326b16a849de7 added some extra
 logging in ElectionState and ClusterConfiguration in order to hunt
 down a bug. It turns out this logging is useful to keep in production
 too. This commits sets proper levels, cleans it up a bit.

Cleans up some superfluous casts that appeared in the code.
Merge pull request #1473 from jakewins/master

Revert "Added additional HA logging."
Add missing test strings to label tutorial.
Make OtherThreadExecutor implement Closeable to make orderly thread
shutdown easier.

o Callers can now use try-with-resources.
Make NestedTransactionLocksIT more readable.
Ensure that all tests close transactions reliably.

o Recent changes to database shutdown mean that we now wait for transactions
   to finish when shutting down. This mean that each of the many tests which did
   not close their transactions was hanging for 20 seconds before failing.
Merge pull request #1463 from chrisvest/fix-impermanent-graph-db-cleanup

ImpermanentGraphDatabase.cleanup should delete all nodes
Merge pull request #1462 from simpsonjulian/goodbye-msi

Remove MSI installer
Rename the GCR Cache to High-Performance Cache
More robust shutdown of sub processes.

o Make PipeTask correctly handle end of input streams.
o Un-export RMI callback so that RMI Reaper thread can exit on owning process.
Merge pull request #1472 from digitalstain/election-logging

Revisits logging in ElectionState and ClusterConfiguration
Added more information about the refnode deprecation. Point to the correct live console server.
Revert "Revert "Added additional HA logging.""

This reverts commit 9950dc2c92ab7fa71b3be32026fb37f56cd64e08.
Resolve incorrectly merged paxos lifecycle management.

o Re-introduce the paxoslife that was removed as part of the merge conflicts.
o Resolves a race condition in which the cluster would hang during switch to slave in
  some alignments of stars.
Fixed the linked list example queries. Moved it to the graphgist format.
Merge pull request #1474 from jakewins/merge-unclosed-txns

Fix unclosed transactions in tests, re-enable proper shutdown cycle.