Remove throws clause from main methods, and exit on Exceptions

This causes the RadarGun processes to exit as soon as an exception is
thrown. I have had issues with the processes not exiting when run in
Jenkins.
Fixes for ISPN-2836

This commit adds support for the new timeout API added in Infinispan
5.3, and adds error handling for exceptions thrown from
MapReduceCapable.executeMapReduceTask()