INT-2517 - Upgrade to Spring 3.1

* Update **build.gradle** and change the *springVersion* property to **3.1.1.RELEASE**
* Due to change in Spring 3.1, add missing method **getRawStatusCode()** in *org.springframework.integration.http.outbound.CookieTests*
Merge pull request #408 from ghillert/INT-2517
INT-2533:GF/ForkUtil fix for -cp with whitespaces
Merge pull request #410 from artembilan/INT-2533
INT-2533: polishing
Merge pull request #416 from artembilan/INT-2533a
INT-2472 Capture Forked Stderr in Tests

Previously, ForkUtil only captured stdout from the forked
process.

Now both stdout and stderr are captured and echoed to
the corresponding PrintStream of the calling process.

Also removed the 200ms delay between each stdout line
captured.
Merge pull request #417 from garyrussell/INT-2472

* INT-2472:
  INT-2472 Capture Forked Stderr in Tests
INT-2535 Update Version to 2.2.0.BUILD-SNAPSHOT

Also update bundlor version ranges for
SI and SF.
Merge pull request #413 from garyrussell/INT-2535

* INT-2535:
  INT-2535 Update Version to 2.2.0.BUILD-SNAPSHOT
INT-2536 Create 2.2 Schemas

Add 2.2 versions of module schemas.

JMX is already covered by an existing pull request.

INT-2536 Schema Check

Bump version for schema check in
AbstractIntegrationNamespaceHandler.

INT-2536 Remove Schema Versions

Some test config files had 2.1 versioned schemas.
Merge pull request #414 from garyrussell/INT-2536

* INT-2536:
  INT-2536 Create 2.2 Schemas
INT-2511 Change Default Socket Timeout

Previously, when a client connection factory was used by
both an inbound and outbound adapter, the socket timeout
defaulted to 10 seconds.

This was inappropriate because, often, collaborating
channel adapters are used for aysnchronous messaaging and,
even when used for request/response, it is generatlly not
appropriate to timeout the socket due to a lack of recent
send activity.
Merge pull request #401 from garyrussell/INT-2511

* INT-2511:
  INT-2511 Change Default Socket Timeout
INT-2538 Prepare Docs For 2.2

* Move What's new in 2.1 to history.
* Add What's new in 2.2 section.
* Add note about caching connections in TCP

INT-2538 Polishing

PR Review comment.
Merge pull request #415 from garyrussell/INT-2538

* INT-2538:
  INT-2538 Prepare Docs For 2.2
INT-1871 TCP CachingClientConnectionFactory

Pool based on algorithm used for spring-integration-file
CachingSessionFactory introduced by INT-2146. Refactored
that code to use the common SimplePool.

One difference to the previous implementation is the
ability to change the pool size dynamically.

If the size is reduced and more than the new size are
in use, items are closed as they are returned until
the pool size is as requested.

Initial commit.

Allow Pool Size Changes

Factor out Pool

Polishing

Pool Tests

Default forever

Javadocs, File

Polishing

INT-1871 PR Polishing

* Consistent/cleaner method names
* Track checkouts; reject release of 'foreign' objects.
* Add 'getAllocatedCount()'
Merge pull request #397 from garyrussell/INT-1871

* INT-1871:
  INT-1871 TCP CachingClientConnectionFactory
INT-1871 Remove Schema Versions

Schemas update to 2.2 after the PR and the new
test config had 2.1 versioned schemas.

INT-1871 polishing, removed unused import
Merge pull request #419 from garyrussell/INT-1871a

* INT-1871a:
  INT-1871 Remove Schema Versions