Query Performance Tests - The word generation for the later search with queries is changed.
New background stressor logic
* checks if each operation's result can be seen from all nodes
* tests GET, PUT, REMOVE (both conditional and non-conditional), PUT_IF_ABSENT, REPLACE (conditional)
* theoretically we may miss some error but there should be no false positives (would be a bug in stressors)
* minor: apache.log4j -> apache.commons (as used in all the rest of framework)
Updated ISPN versions
Fix for cross-site tests: Using key generator
Add Map/Reduce and Distributed Task cachewrappers for Infinispan 6
Variable entry size in stress tests
Removed CacheWrapper as the superinterface for features
Refactored Infinispan cache wrapper hieararchy
* All wrappers should from now on keep linear hierarchy according to Infinispan versions (one wrapper per plugin)
* Each feature should be implemented by separate object - wrapper and feature can be enriched separately
* Code from the core wrapper moved to Lifecycle and BasicOperations (these are not features) - wrapper should only hold the caches and orchestrate features
* InfinispanWrapper now can work as multi-cache wrapper as well (see StressTest.useBuckets)
Add support for MapReduceTask combiners

Infinispan 5.2 added the ability to specify a Reducer that would be used
to reduce the values on the local node before the global reduce phase is
executed. This commit adds support for specifying this option in the
MapReduceStage parameters and implements support for them in the
MapReduceCapable interface and InfinispanMapReduce class.
Updated Infinispan version for JDG 6.2 plugin
Fix: in TX context the entries written in one transactions can be committed in different order
JGroups plugins for different versions. Removed configuration properties.
Support for batching (replaces transactions in the test)