ISPN-2284 Execute Mapper and Reducer tasks in parallel where possible
ISPN-3946 Ensure M/R intermediate key/value transfer is chunked properly
ISPN-3967 Create a feature file for HotRod client for easy installation in Karaf

* add tests for HotRod client running in Karaf
* modify export/import directives for some modules so that they run in OSGi