update JGroups to 3.3.0.CR2 and Infinispan 5.2.6-cloudtm-SNAPSHOT
Merge pull request #135 from pruivo/update

update JGroups to 3.3.0.CR2 and Infinispan 5.2.6-cloudtm-SNAPSHOT
Avoid creating Exception when tx is null

  * The contract for TransactionManager.getTransaction() states that it should
    return null when there is no transaction. The previous code was catching a
    NullPointerException to return null, which was far more expensive than
    just testing for null.

  * This commit applies 8a3d29e61c4763bd23850a3d912ae338e5a14f58 from the
  develop branch.
BugFix: Use WeakReference to enable GC of deletageTx in JTADelegatingTransaction

  * TxMap holds a static
    Map<WeakReference<javax.transaction.Transaction>>,JTADelegatingTransaction>
    to enable collection of transactions used as keys.  However, because each
    entry's value (JTADelegatingTransaction) is strongly held in the map and,
    in turn, such value held a strong reference to
    javax.transaction.Transaction, the latter was never really collectable.
    This commit fixes this issue by turning the strong reference into a
    WeakReference.

  * This commit applies 03683b2a21c75abcdc7550e77722f1dab7463b05 from the
    develop branch.
Bump version to 2.5-cloudtm-SNAPSHOT
Implemented method to return the cluster information, if available.
Merge pull request #144 from pruivo/cluster_info

Implemented method to return the cluster information, if available.
Bump version to 2.6-cloudtm-SNAPSHOT
Shutdown didn't set initialized to false

It was preventing the Fenix Framework to be shutdown and initialized multiple times.
Bugfix: the decode didn't check the string length while parsing

An Exception was thrown while tried to decode the locality hints + the field name (key format is class@uuid@hints:field)
Don't force the LocalityHints to have the KeyFeatureManager

The LocalityHints is used in Grouping and it is independent of auto-placer's KeyFeatureManager.
Multiple improvements in Infinispan Backend.

* Support to Grouping API by injecting Fenix Framework Grouper.
* Support to creation of InifinispanConfig instead of parsing the properties file.
* Support to set the Infinispan configuration programatically without infinispan configuration file.
* Initialize the LocalityHints with the KeyFeatureManager if auto-placer + Machine Learner is enabled.
* Added test cases for Grouping.
Improve write operations.

Decorate a cache for write that ignores the return value of Object put(key,value).
In distributed mode it reduces the write costs by skiping possible remote gets.
Merge pull request #146 from pruivo/grouping_and_autoplacer

Improvements/new implementation for Cloud-TM branch
Prepare release 2.6-cloudtm
Bump version to 2.7-cloudtm-SNAPSHOT
Fix Infinispan version

It got skewed when bumping the FF to the next snapshot version.
Support setting B+Tree LOWER_BOUND via configuration

  Use config property 'btreeLowerBound'.  This affects both BPlusTree and
  BPlusTreeArray implementations.
Prepare release 2.7-cloudtm
Bump version to 2.8-cloudtm-SNAPSHOT