Updates poms to 1.9.10-SNAPSHOT
Merge pull request #3254 from davidegrohmann/2.2-ref-counts-store

[2.2] Counts Store refactor to be based on a generic KV-Store
Re-enables parallel I/O in batch importer
Add additional tests for X-Forwarded-Host

Against Cypher REST response, and slash redirects
Changed the code so that the transactional endpoint creates URIs based on the request URI (rather than the server's URI). This is better (the server doesn't usually know it's own URI, whereas clients do) and enables X-Forward headers to work, fixing the problem identified in https://gist.github.com/albertoperdomo/6f3d7ffcb1351e5c61ce

However, /db/data and /db/manage (note: no trailing slashes) are not fixed here. That is a different bit of code to tame.
Merge pull request #3191 from jakewins/2.2-slavesessions

[2.2] Resolve two race conditions relating to HA lock sessions
Reduces contention in ArrayQueueOutOfOrderSequence#get

by removing synchronized on the method and letting the member variable
containing the high id by volatile.
Make Rewriter a total function (AnyRef => AnyRef) rather than (AnyRef => Option[AnyRef])

In practice, some combinators already made assumptions about it being the case.
There doesn't seem to be a benefit for the partiality other than a short-circuit in repeat().
However, we rely on identity equality to be roughly as performant as a runtime check
for whether Option[AnyRef] is Some(_) or None.
Various optimisations in planning of hot spots found when profiling
Merge pull request #3209 from jakewins/2.2-txpool

[2.2] Introduce pooling of KernelTransactions.
Merge pull request #3273 from tinwelint/2.2-reduce-ooos-contention

[2.2] Reduces contention in ArrayQueueOutOfOrderSequence#get
Removed the integration tests pertaining to the correct use of X-Forward-* when redirecting from URIs that don't end in slash to ones that do*.

This is because there is some subtle interaction between Jetty and Jersey that screws this up. We've been through the Jetty code trying to see where this happens, but it's high cost for low value. Therefore when you don't correctly specify (say) /db/mabage/ and instead specify /db/manage then you will likely get incorrect URIs in the 302 response. the solution is not to use the wrong URI.

* This is a dumb decision by Jetty/Jersey. It is clear that http://example.com/foo/ and http://example.com/foo are not the same URI. Meh.
Use heartbeat URL from settings and suffix a slash.
Merge pull request #3270 from pontusmelke/profiling-changes

[2.2] Change Rewriter to be a total function
[2.2] Remove iterator from itereateUntilConverged

Profiling indicates that a minor tweak in iterateUntilConverged leads to (minor) speed up of compiling.
Merge pull request #3277 from jimwebber/master

[2.2] X-Forward Support for Transactional Endpoint
Manage position ourselves in PhysicalLogVersionStoreChannel

since it's expensive enough, especially on Windows, to show up in
profiling.
Tweak for number of files opened by Lucene
Changed the test implementation so that all tests use the same impermanent server instance (they don't change server state after all).
Merge pull request #3271 from chrisvest/2.2-pagecache-stress

[2.2] Fix a page cache bug that can lead to lost updates